The 66th Delaware General Assembly was a meeting of the legislative branch of the state government, consisting of the Delaware Senate and the Delaware House of Representatives. Elections were held the first Tuesday after November 1 and terms began on the first Tuesday in January. It met in Dover, Delaware, convening January 7, 1851, two weeks before the beginning of the first and second year of the administration of Governor William H.H. Ross.

The apportionment of seats was permanently assigned to three senators and seven representatives for each of the three counties. Population of the county did not effect the number of delegates. Both chambers had a Democratic majority.

• Martin, Roger A. (1995). Memoirs of the Senate. Newark, Delaware: Roger A. Martin.

• Delaware Historical Society; website; 505 North Market Street, Wilmington, Delaware 19801; (302) 655-7161
• University of Delaware; Library website; 181 South College Avenue, Newark, Delaware 19717; (302) 831-2965