Usually the bank making the loan has to hold the loan in their own portfolio and take the chance that interest rates will go up which will make your mortgage a bad investment for them. Colonial Farm Credit is the only exception to this rule, they make land loans all over the U.S. and package them and sell them just like your house mortgage is done. That's why they can give you a 20 year fixed rate because they pass the interest rate risk on to the investors who buy their bonds. They have a toll-free line from which they can connect you with the office closest to you. If you are a member of a credit union they sometimes have very good terms for their customers.
Some people also borrow against their profit sharing as well.
The money to buy the piece of land you want may be in your own home. Many customers either refinance their home or get equity lines against it. This also has the advantage of meaning the interest you pay will probably be tax deductible. This method naturally assumes you have equity in your home. Some smaller rural banks are excellent sources for land loans.