The Brazos Santiago channel and seaward approach is defined by parallel jetties designed with a breakwater separation of .25 miles (0.40 km).

The natural ocean inlet has a shoreline distance on Brazos Island of 7.5 miles (12.1 km) to the Rio Grande often entitled as the Mexico–United States border.

[9] In 1879, a screw-pile lighthouse was established in the intertidal zone of the Lower Laguna Madre with a geographic proximity to the Brazos Santiago Pass.

[10] The deep foundation architecture was acknowledged as a notable landmark sight for sixty years within the Texas international boundary region of the Lower Rio Grande Valley coast.

[13][14][15] The upper quarters were structured as a 1½ storey hexagonal Cape Cod style cottage built of timbers completed with a fourth-order fresnel lens located at the pinnacle.