[6] As of the 2020 United States census, there were 20,383 people, 6,136 households, and 4,639 families residing in the city.

As of the census[3] of 2000, 14,827 people, 5,021 households, and 4,051 families were residing in the city.

About 16.1% of all households were made up of individuals, and 6.1% had someone living alone who was 65 years of age or older.

The original 640-acre townsite of Portland was purchased by John G. Willacy in 1890.

In 1891, Willacy sold the land to the Portland (Maine) Harbor and Improvement Co. Portland is situated on the second-highest bluff on the Gulf Coast and overlooks both Nueces and Corpus Christi Bays.

[12] In 2022, Portland had a crime index lower than the U.S. average and half that of Texas.