As a general matter, two daycares could be next to each other; two of any kind of business could be next to each other. However, munipalities (towns, cities, etc.) can and sometimes do passing zoning ordinances (rules) requiring certain minimum distances between similar businesses (oddly enough, in my area, this is common for beauty product stores, for example...they often need 500 foot separations). So to be sure, contct your municipal clerk's ofice and also the office of code enforcement (zoning) and ask about any local rules you have to comply with.