As of 2023, 97.7% of Terrebonne Parish, LA residents were US citizens, which is higher than the national average of 93.4%. In 2022, the percentage of US citizens in Terrebonne Parish, LA was 98.5%, meaning that the rate of citizenship has been decreasing.

The following chart shows US citizenship percentages in Terrebonne Parish, LA compared to that of it's neighboring and parent geographies.