Welcome to Port Isabel. Before you get your adventure underway, it’s always a good idea to know a few basic facts about the area. So flatten out your map, grab a pen and listen up.This town sits 22 miles to the northeast of Brownsville, and 1,491 miles southwest of Washington, the nation’s capital.It can be useful to know how many people reside in the place you’re planning to visit. In this part of South Padre Island, the population is around 5,000.