Bolivar is a narrow peninsula on the upper Texas coast between the Gulf of Mexico and East Galveston Bay. It lies in a northeasterly direction separated from Galveston Island by the Houston Ship Channel and the Bolivar Roads, 3 miles wide. Free Public Ferries link the Peninsula with Galveston Island.

The Peninsula is called "an offshore sandbar at the eastern end of a chain of islands extending along the Texas and Mexico coasts". The widest point of the Peninsula's 27 miles is between Crystal Beach and Caplen, (about 3 1/2 miles). It is also known as a barrier peninsula.

Bolivar Peninsula was named in honor of Simon Bolivar (1783-1836), a freedom leader fighting to free South and Central America from Spanish rule.