<PAGE>

                                                                   EXHIBIT 4.2


                          REGISTRATION RIGHTS AGREEMENT


     THIS REGISTRATION RIGHTS AGREEMENT (the "Agreement") is dated as of the 1st
day of October, 2001, by and among Boston Private Financial Holdings, Inc., a
Massachusetts corporation (the "Company"), and the person designated as a Holder
on the signature pages hereto and any assignees or transferees thereof who
become Holders in accordance with Section 8 hereof (each, a "Holder" and
collectively, the "Holders").

     WHEREAS, the Company and certain parties including the Holder have entered
into a certain Agreement and Plan of Merger dated as of June 29, 2001 (the
"Merger Agreement"), pursuant to which the Holder will receive shares of Common
Stock, par value $1.00 per share (the "Common Stock"), of the Company in
connection with the closing of the transactions contemplated thereby; and

     WHEREAS, the execution of this Agreement is an inducement and a condition
to the consummation by the Holder of the transactions contemplated by the Merger
Agreement.

     NOW, THEREFORE, in consideration of the foregoing and the mutual promises
of the parties herein contained, and for other good and valuable consideration,
the receipt and sufficiency of which are hereby acknowledged, the Company and
the Holders hereby covenant and agree with each other as follows:

     1.  CERTAIN DEFINITIONS. As used in this Agreement, the following terms
shall have the following respective meanings:

         "BOARD" means the Board of Directors of the Company.

         "COMMISSION" shall mean the United States Securities and Exchange
Commission, or any other federal agency at the time administering the Securities
Act and the Exchange Act.

         "COMMON STOCK" shall mean the Common Stock and any other common equity
securities issued by the Company, and any other shares of stock issued or
issuable with respect thereto (whether by way of a stock dividend or stock split
or in exchange for or upon conversion of such shares, recapitalization, merger,
consideration or other corporate reorganization).

         "COMPANY" shall refer to the Company and any successor or successors
thereto.

         "EXCHANGE ACT" shall mean the Securities Exchange Act of 1934, as
amended, or any similar successor federal statute, and the rules and regulations
of the Commission thereunder, all as the same shall be in effect at the time.

         "MAJORITY INTEREST" means the Holders holding not less than a majority
of the Registrable Securities held by all Holders.


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         "PERSON" shall mean an individual, a corporation, an association, a
joint venture, a partnership, a limited liability company, an estate, a trust,
an unincorporated organization, and any other entity or organization,
governmental or otherwise.

         "REGISTRABLE SECURITIES" shall mean (i) any shares of Common Stock
received by the Holder or his transferees in connection with the transactions
contemplated by the Merger Agreement and (ii) any other securities issued or
issuable with respect to any such shares described in clause (i) above by way of
a stock dividend or stock split or in connection with a combination of shares,
recapitalization, merger, consolidation or other reorganization; PROVIDED,
HOWEVER, that notwithstanding anything to the contrary contained herein,
"Registrable Securities" shall not at any time include any securities (i)
theretofore registered and sold pursuant to the Securities Act, (ii) theretofore
sold to the public pursuant to Rule 144 promulgated under the Securities Act or
(iii) which could then be sold in their entirety pursuant to Rule 144(k)
promulgated under the Securities Act without limitation or restriction.

         "REGISTRATION EXPENSES" shall mean the expenses so described in Section
4 hereof.

         "SECURITIES ACT" shall mean the Securities Act of 1933 or any similar
successor federal statute, and the rules and regulations of the Commission
thereunder, all as the same shall be in effect at the time.

2. PIGGYBACK REGISTRATION. If the Company at any time proposes to register any
of its Common Stock under the Securities Act for sale to the public (except with
respect to any registration statement on Form S-4, S-8 or any other form not
available for registering the Registrable Securities for sale to the public) (a
"Piggy-Back Registration"), each such time it will promptly give written notice
to each holder of Registrable Securities of its intention to effect such
registration. Upon the written request of any such holder of Registrable
Securities given within thirty (30) days after receipt by such holder of such
notice, the Company will, subject to the limits contained in this Section 2, use
its commercially reasonable efforts to cause all of the Registrable Securities
of such holder that such holder so requests to be registered under the
Securities Act and qualified for sale under any state blue sky law, all to the
extent required to permit such sale or other disposition of said Registrable
Securities; PROVIDED, HOWEVER, that if the Company is advised in writing in good
faith by the managing underwriter of the Company's securities being offered in
an underwritten public offering pursuant to such registration statement that the
amount to be sold by persons other than the Company (collectively, "Selling
Stockholders") is greater than the amount which can be offered without adversely
affecting the marketability of the offering, the Company may reduce the amount
offered for the accounts of Selling Stockholders (including any holders of
Registrable Securities) to a number reasonably deemed satisfactory by such
managing underwriter; and PROVIDED, FURTHER, that the securities to be excluded
shall be determined in the following sequence: (i) first, securities held by any
Persons not having any contractual incidental or "piggy back" registration
rights, (ii) second, securities held by any other Persons (other than Persons
holding Registrable Securities) having contractual incidental or "piggyback"
registration rights subordinate in priority to the registrations rights granted
to the Holders hereunder, (iii) third, Registrable Securities held by the
Holders or securities held by other Persons having contractual incidental or
"piggyback" registration rights equal in priority to the registrations rights
granted to the Holders hereunder


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and (iv) fourth, securities held by any other Persons (other than Persons
holding Registrable Securities) having contractual incidental or "piggyback"
registration rights superior in priority to the registrations rights granted to
the Holders hereunder. If there is a reduction in the number of shares of Common
Stock or Registrable Securities to be registered pursuant to clauses (i), (ii),
(iii) or (iv) above, such reduction shall be made within each tranche on a pro
rata basis (based upon the aggregate number of shares of Common Stock or
Registrable Securities held by the holders in each such tranche and subject to
the priorities set forth in the preceding sentence).

     3.  REGISTRATION PROCEDURES. If and whenever the Company is required by the
provisions of this Agreement to effect the registration of any of its securities
under the Securities Act, the Company will, as soon as practicable:

         (a) use its commercially reasonable efforts to prepare and file with
the Commission a registration statement on the appropriate form under the
Securities Act with respect to such securities, which form shall comply as to
form in all material respects with the requirements of the applicable form and
include all financial statements required by the Commission to be filed
therewith, and use its commercially reasonable efforts to cause such
registration statement to become and remain effective until completion of the
proposed offering (but not for more than one hundred eighty (180) days);

         (b) use its commercially reasonable efforts to prepare and file with
the Commission such amendments and supplements to such registration statement
and the prospectus used in connection therewith as may be necessary to keep such
registration statement effective until the completion of the offering (but not
for more than one hundred eighty (180) days) and to comply with the provisions
of the Securities Act with respect to the sale or other disposition of all
securities covered by such registration statement whenever the seller or sellers
of such securities shall desire to sell or otherwise dispose of the same, but
only to the extent provided in this Agreement;

         (c) furnish to each selling holder and the underwriters, if any, such
number of copies of such registration statement, any amendments thereto, any
documents incorporated by reference therein, the prospectus, including a
preliminary prospectus, all in conformity with the requirements of the
Securities Act, and such other documents as such selling holder may reasonably
request in order to facilitate the public sale or other disposition of the
securities owned by such selling holder;

         (d) use its commercially reasonable efforts to register or qualify the
securities covered by such registration statement under and to the extent
required by such other securities or state blue sky laws of such jurisdictions
as each selling holder shall reasonably request, and do any and all other acts
and things which may be necessary under such securities or blue sky laws to
enable such selling holder to consummate the public sale or other disposition in
such jurisdictions of the securities owned by such selling holder, except that
the Company shall not for any such purpose be required to qualify to do business
as a foreign corporation in any jurisdiction wherein it is not so qualified or
submit to service of process in any jurisdiction in which it is not already
subject;


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         (e) within a reasonable time before each filing of the registration
statement or prospectus or amendments or supplements thereto with the
Commission, furnish to a single counsel selected by the holders of Registrable
Securities proposing to include shares in such registration copies of such
documents proposed to be filed, which information in such documents pertaining
to such holders shall be subject to the reasonable approval of such counsel;

         (f) promptly notify each selling holder of Registrable Securities, such
selling holders' counsel and any underwriter and (if requested by any such
Person) confirm such notice in writing, of the happening of any event which
makes any statement made in the registration statement or related prospectus
untrue or which requires the making of any changes in such registration
statement or prospectus so that they will not contain any untrue statement of a
material fact or omit to state any material fact required to be stated therein
or necessary to make the statements therein, in the light of the circumstances
under which they were made, not misleading; and, as promptly as practicable
thereafter, prepare and file with the Commission and furnish a supplement or
amendment to such prospectus so that, as thereafter deliverable to the
purchasers of such Registrable Securities, such prospectus will not contain any
untrue statement of a material fact or omit to state a material fact necessary
to make the statements therein, in the light of the circumstances under which
they were made, not misleading;

         (g) use its commercially reasonable efforts to prevent the issuance of
any order suspending the effectiveness of a registration statement, and if one
is issued use its commercially reasonable efforts to obtain the withdrawal of
any order suspending the effectiveness of a registration statement at the
earliest possible moment;

         (h) if requested by the managing underwriter or underwriters (if any),
any selling holder, or counsel to the selling holders, promptly incorporate in a
prospectus supplement or post-effective amendment such information as such
Person requests to be included therein with respect to the selling holder or the
securities being sold, including, without limitation, with respect to the
securities being sold by such selling holder to such underwriter or
underwriters, the purchase price being paid therefor by such underwriter or
underwriters and with respect to any other terms of an underwritten offering of
the securities to be sold in such offering, and promptly make all required
filings of such prospectus supplement or post-effective amendment;

         (i) make available to each selling holder, any underwriter
participating in any disposition pursuant to a registration statement, and a
single attorney and accountant retained by any such selling holders or
underwriters (collectively, the "Inspectors"), all financial and other records,
pertinent corporate documents and properties of the Company as shall be
reasonably necessary to enable them to exercise their due diligence
responsibility, and cause the Company's officers, directors and employees to
supply all information reasonably requested by any such Inspector in connection
with such registration statement subject, in each case, to such confidentiality
agreements as the Company shall reasonably request;

         (j) request that each prospective selling holder be furnished a signed
counterpart, addressed to the prospective selling holder, of (i) an opinion of
counsel for the Company, dated the effective date of the registration statement,
and (ii) if and to the extent permitted by applicable professional standards, a
"comfort" letter signed by the independent public accountants who have certified
the Company's financial statements included in the


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registration statement, covering substantially the same matters with respect to
the registration statement (and the prospectus included therein) and (in the
case of the accountants' letter) with respect to events subsequent to the date
of the financial statements, as are customarily covered (at the time of such
registration) in opinions of the Company's counsel and in accountants' letters
delivered to the underwriters in underwritten public offerings of securities;

         (k) use its commercially reasonable efforts to cause the securities
covered by such registration statement to be listed on the securities exchange
or quoted on the quotation system on which the Common Stock is then listed or
quoted (or, if the Common Stock is not yet listed or quoted, then on such
exchange or quotation system as the selling holders of Registrable Securities
and the Company shall determine);

         (l) otherwise use its commercially reasonable efforts to comply with
all applicable rules and regulations of the Commission and make generally
available to its security holders, in each case as soon as practicable, but not
later than ninety (90) days after the close of the period covered thereby, an
earnings statement of the Company which will satisfy the provisions of Section
11(a) of the Securities Act and Rule 158 thereunder (or any comparable successor
provisions); and

         (m) otherwise cooperate with the Holders, the underwriter(s), if any,
the Commission and other regulatory agencies and take all reasonable actions and
execute and deliver or cause to be executed and delivered all documents
reasonably necessary to effect the registration of any securities under this
Agreement.

     4.  EXPENSES. All reasonable expenses incurred by the Company, the Holders
in effecting the registrations provided for in Section 2 hereof, including,
without limitation, all registration and filing fees, printing expenses, fees
and disbursements of counsel for the Company, fees and disbursements of one
counsel for the Holders, underwriting expenses (other than fees, commissions or
discounts of selling holders), expenses of any audits incident to or required by
any such registration and expenses of complying with the securities or blue sky
laws of any jurisdiction pursuant to Section 3(d) hereof (all of such expenses
referred to as "Registration Expenses"), shall be paid by the Company.

     5.  INDEMNIFICATION.

         (a) The Company shall indemnify and hold harmless each selling holder
of Registrable Securities, each underwriter (as defined in the Securities Act),
and each other Person who participates in the offering of such securities and
each other Person, if any, who controls (within the meaning of the Securities
Act) such seller, underwriter or participating Person (individually and
collectively, the "Indemnified Persons"), against any losses, claims, damages,
liabilities and expenses (collectively, the "liability") to which such
Indemnified Persons may become subject under the Securities Act or any other
statute or at common law, insofar as such liability (or action in respect
thereof) arises out of or is based upon (i) any untrue statement or alleged
untrue statement of any material fact contained in any registration statement
under which such securities were registered under the Securities Act, any
preliminary prospectus or final


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prospectus contained therein, or any amendment or supplement thereto, or (ii)
any omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading.
Except as otherwise provided in Section 5(d) hereof, the Company shall reimburse
each such Indemnified Person in connection with investigating or defending any
such liability as expenses in connection with the same are incurred; PROVIDED,
HOWEVER, that the Company shall not be liable to any Indemnified Person in any
such case to the extent that any such liability arises out of or is based upon
any untrue statement or alleged untrue statement or omission or alleged omission
made in such registration statement, preliminary or final prospectus, or
amendment or supplement thereto in reliance upon and in conformity with
information furnished in writing to the Company by such Indemnified Person
specifically for use therein.

         (b) Each selling holder of any securities included in such registration
being effected shall indemnify and hold harmless each other selling holder of
any securities, the Company, its directors and officers, each underwriter and
each other Person, if any, who controls any such selling holder, the Company or
such underwriter (individually and collectively, the "Indemnified Persons"),
against any liability, severally and not jointly, to which any such Indemnified
Person may become subject under the Securities Act or any other statute or at
common law, insofar as such liability (or actions in respect thereof) arises out
of or is based upon (i) any untrue statement or alleged untrue statement of any
material fact contained, on the effective date thereof, in any registration
statement under which securities were registered under the Securities Act at the
request of such selling holder, any preliminary prospectus or final prospectus
contained therein, or any amendment or supplement thereto, or (ii) any omission
or alleged omission by such selling holder to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, in the case of (i) and (ii) to the extent, but only to the extent,
that such untrue statement or alleged untrue statement or omission or alleged
omission was made in such registration statement, preliminary or final
prospectus, amendment or supplement thereto in reliance upon and in conformity
with information furnished in writing to the Company by such selling holder
specifically for use therein. Such selling holder shall reimburse any
Indemnified Person for expenses (including, without limitation, legal fees)
incurred in investigating or defending any such liability; PROVIDED, HOWEVER,
that such selling holder's obligations hereunder shall be limited to an amount
equal to the net proceeds received by such selling holder for the securities
sold in any such registration.

         (c) Indemnification similar to that specified in Section 5(a) and
Section 5(b) hereof shall be given by the Company and each selling holder (with
such modifications as may be appropriate) with respect to any required
registration or other qualification of their securities under any federal or
state law or regulation of governmental authority other than the Securities Act.

         (d) If the indemnification provided for in this Section 5 for any
reason is held by a court of competent jurisdiction to be unavailable to an
Indemnified Person in respect of any losses, claims, damages, expenses or
liabilities referred to therein, then each indemnifying party under this Section
5, in lieu of indemnifying such Indemnified Person thereunder, shall contribute
to the amount paid or payable by such indemnified party as a result of such
losses, claims, damages, expenses or liabilities (i) in such proportion as is
appropriate to reflect the


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relative benefits received by the Company, the selling holders and the
underwriters from the offering of the Registrable Securities or (ii) if the
allocation provided by clause (i) above is not permitted by applicable law, in
such proportion as is appropriate to reflect not only the relative benefits
referred to in clause (i) above, but also the relative fault of the Company, the
other selling holders and the underwriters in connection with the statements or
omissions which resulted in such losses, claims, damages, expenses or
liabilities, as well as any other relevant equitable considerations. The
relative benefits received by the Company, the selling holders and the
underwriters shall be deemed to be in the same respective proportions as the net
proceeds from the offering (before deducting expenses) received by the Company
and the selling holders and the underwriting discount received by the
underwriters, in each case as set forth in the table on the cover page of the
applicable prospectus, bear to the aggregate public offering price of the
Registrable Securities. The relative fault of the Company, the selling holders
and the underwriters shall be determined by reference to, among other things,
whether the untrue or alleged untrue statement of a material fact or the
omission or alleged omission to state a material fact relates to information
supplied by the Company, the selling holders or the underwriters and the
parties' relative intent, knowledge, access to information and opportunity to
correct such statement or omission.

         The Company, the selling holders and the underwriters agree that it
would not be just and equitable if contribution pursuant to this Section 5 were
determined by pro rata or per capita allocation or by any other method of
allocation which does not take into account the equitable considerations
referred to in the immediately preceding paragraph. In no event, however, shall
a selling holder be required to contribute any amount under this Section 5(d) in
excess of the lesser of (i) that proportion of the total of such losses, claims,
damages, liabilities or expenses indemnified against equal to the proportion of
the total Registrable Securities sold under such registration statement which
are being sold by such selling holder or (ii) the net proceeds received by such
selling holder from its sale of Registrable Securities under such registration
statement. No person found guilty of fraudulent misrepresentation (within the
meaning of Section 11(f) of the Securities Act) shall be entitled to
contribution from any person who was not found guilty of such fraudulent
misrepresentation.

     6.  COMPLIANCE WITH RULE 144. The Company shall use its commercially
reasonable efforts to take all action as may be required as a condition to the
availability of Rule 144 under the Securities Act (or any comparable successor
rules). The Company shall furnish to any holder of Registrable Securities upon
request a written statement executed by the Company as to the steps it has taken
to comply with the current public information requirement of Rule 144 (or such
comparable successor rules).

     7.  AMENDMENTS. The provisions of this Agreement may be amended only with
the written consent of the Company and a Majority Interest, and the Company may
take any action herein prohibited or omit to perform any act herein required to
be performed by it only with the written consent of a Majority Interest.


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     8.  TRANSFERABILITY OF REGISTRATION RIGHTS. The registration rights set
forth in this Agreement are transferable to each transferee of at least 10,000
shares of Registrable Securities (as adjusted for stock splits, stock dividends,
reorganizations, recapitalizations or other similar changes in the Registrable
Securities), which such transferees may include any trust, limited partnership
or other estate planning vehicle, the primary beneficiaries or equity holders of
which are the transferring holder and/or one or more of a spouse, parent,
sibling, child or grandchild of such holder or any charitable trust or
foundation. Each subsequent holder of Registrable Securities must consent in
writing to be bound by the terms and conditions of this Agreement in order to
acquire the rights granted pursuant to this Agreement.

     9.  RIGHTS WHICH MAY BE GRANTED TO SUBSEQUENT HOLDERS; PRIORITY OF
REGISTRATION RIGHTS. Other than transferees of Registrable Securities under
Section 8 hereof, the Company shall not, without the prior written consent of a
Majority Interest, allow subsequent purchasers of the Company's securities to
become a party to this Agreement. The registration rights granted to the holders
hereunder shall be (i) subordinate to the registration rights granted pursuant
to that certain Registration Rights Agreement dated as of August 31, 2000 by and
among the Company and certain stockholders of the Company named therein, and
(ii) equal in priority to the registration rights granted pursuant to that
certain Registration Rights Agreement dated as of February 28, 2001 by and among
the Company and certain stockholders of the Company named therein.

     10. DAMAGES. The Company recognizes and agrees that each holder of
Registrable Securities will not have an adequate remedy if the Company fails to
comply with the terms and provisions of this Agreement and that damages will not
be readily ascertainable, and the Company expressly agrees that, in the event of
such failure, it shall not oppose an application by any holder of Registrable
Securities or any other Person entitled to the benefits of this Agreement
requiring specific performance of any and all provisions hereof or enjoining the
Company from continuing to commit any such breach of this Agreement.

     11. MISCELLANEOUS.

         (a) Any notice, request, demand or other communication required or
permitted hereunder shall be in writing and shall be deemed to have been given
if delivered or sent by facsimile transmission, upon receipt, if sent by a
recognized overnight delivery service, upon the next business day, or if sent by
registered or certified mail, upon the sooner of the date on which receipt is
acknowledged or the expiration of three days after deposit in United States post
office facilities properly addressed with postage prepaid. All notices to a
party will be sent to the addresses set forth below or to such other address or
person as such party may designate by notice to each other party hereunder:


         IF TO THE COMPANY:         Boston Private Financial Holdings, Inc.
                                    Ten Post Office Square
                                    Boston, MA 02109
                                    Facsimile: (617) 912-4551
                                    Attention: Walter M. Pressey


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            WITH A COPY TO:         Goodwin Procter  LLP
                                    Exchange Place
                                    Boston, MA 02109-2881
                                    Facsimile:  (617) 523-1231
                                    Attention:  William P. Mayer, Esq.
                                    Charles H. Sturdy, Esq.

         IF TO THE HOLDERS:         William M. Dougherty
                                    c/o Kanon Bloch Carre
                                    10 Post Office Square
                                    Boston, MA 02109
                                    Facsimile: (617) 423-3206

            WITH A COPY TO:         Hutchins, Wheeler & Dittmar,
                                    A Professional Corporation
                                    101 Federal Street
                                    Boston, MA  02110
                                    Facsimile:  (617) 951-1295
                                    Attention:  Joseph C. Tanksi, Esq.
                                    David M. Barbash, Esq.

         IF TO ANY OTHER HOLDER OF REGISTRABLE SECURITIES:

                                    At such Person's address for notice
                                    as set forth in the books and
                                    records of the Company.

or, as to each of the foregoing, at such other address as shall be designated by
such Person in a written notice to other parties complying as to delivery with
the terms of this subsection (a). All such notices, requests, demands and other
communications shall, when mailed or sent, respectively, be effective (i) two
days after being deposited in the mails or (ii) one day after being deposited
with a same-day or express overnight courier service or sent by electronic
facsimile transmission, respectively, addressed as aforesaid. (b) This Agreement
shall be governed by and construed in accordance with the laws of the
Commonwealth of Massachusetts without giving effect to conflict of laws
principles thereof.

         (c) This Agreement may be executed in two or more counterparts, each of
which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

         (d) If any provision of this Agreement shall be held to be illegal,
invalid or unenforceable, such illegality, invalidity or unenforceability shall
attach only to such provision and shall not in any manner affect or render
illegal, invalid or unenforceable any other provision of this Agreement, and
this Agreement shall be carried out as if any such illegal, invalid or
unenforceable provision were not contained herein.


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         IN WITNESS WHEREOF, the parties hereto have caused this Registration
Rights Agreement to be duly executed as of the date first set forth above.

COMPANY:                        BOSTON PRIVATE FINANCIAL HOLDINGS, INC.


                                By:    /s/ Walter M. Pressey
                                       -------------------------------
                                Name:  Walter M. Pressey
                                Title: President and Chief Financial Officer


HOLDER:

                                /s/ William M. Dougherty
                                -------------------------------------
                                William M. Dougherty