Trinity Bay is the northeast portion of Galveston Bay

Galveston Bay

Galveston Bay is a large estuary located along the upper coast of Texas in the United States. It is connected to the Gulf of Mexico and is surrounded by sub-tropic marshes and prairies on the mainland. The water in the Bay is a complex mixture of sea water and fresh water which supports a wide...

, bordered by Chambers and Harris

Harris County, Texas

As of the 2010 Census, the population of the county was 4,092,459, White Americans made up 56.6% of Harris County's population; non-Hispanic whites represented 33.0% of the population. Black Americans made up 18.9% of the population. Native Americans made up 0.7% of Harris County's population...

 counties in Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. The bay, approximately 20 miles (32 km) long, heads at the mouth of the Trinity River

Trinity River (Texas)

The Trinity River is a long river that flows entirely within the U.S. state of Texas. It rises in extreme north Texas, a few miles south of the Red River. The headwaters are separated by the high bluffs on the south side of the Red River....

. Trinity Bay is separated from the main part of Galveston Bay by the San Jacinto River, part of the Houston Ship Channel

Houston Ship Channel

The Houston Ship Channel, located in Houston, Texas, is part of the Port of Houston—one of the United States's busiest seaports. The channel is the conduit for ocean-going vessels between the Houston-area shipyards and the Gulf of Mexico.-Overview:...

.

Trinity Bay fronts on the vast network of Chambers County marshes and prairie land. The Trinity Basin contributes 54% of the total bay system inflow for the Galveston Bay complex. Near the head of the bay sits the town of Anahuac

Anahuac, Texas

Anahuac is a city in the U.S. state of Texas within the Houston–Sugar Land–Baytown metropolitan area. The population of the city was 2,210 at the 2000 census. Anahuac is the seat of Chambers County and is situated in East Texas.- History :...

. Closer to the San Jacinto river lies the community of Beach City

Beach City, Texas

Beach City is a city in Chambers County, Texas, United States. The population was 1,645 at the 2000 census.-Geography:Beach City is located at ....

. The city of Baytown

Baytown, Texas

Baytown is a city within Harris County and partially in Chambers County in the Gulf Coast region of the U.S. state of Texas. Located within the Houston–Sugar Land–Baytown metropolitan area, it lies along both State Highway 146 and Interstate 10. As of 2010, Baytown had an population of 71,802...

 also lies near the bay although it does not actually reach its shores. Some smaller communities hug the shores of the bay as well. Much of the area near the shore is semi-rural or undeveloped, particularly the Anahuac National Wildlife Refuge

Anahuac National Wildlife Refuge

The Anahuac National Wildlife Refuge is a wildlife conservation area along the coast of Texas , west of the town of High Island, Texas. It borders East Bay, part of the Galveston Bay complex, behind Bolivar Peninsula at the Gulf of Mexico....

which lies between Trinity Bay and East Bay, another segment of the Galveston Bay complex.