[3] It is named for the Lavaca River, which curves its way southeast through Moulton and Hallettsville before reaching the coast at Matagorda Bay.

[5] As of the census[11] of 2000, 19,210 people, 7,669 households, and 5,391 families were residing in the county.

Of descent, 27.0% were of Czech, 24.1% German, 9.1% American, and 5.1% Irish ancestry according to Census 2000; 86.3% spoke English, 7.7% Spanish, 4.6% Czech and 1.2% German as their first language.

In terms of ancestry in 2016, 32.8% were of German, 30.7% were of Czech, 10.8% were of Irish, 5.4% were of English, 3.4% were of American, and 2.2% were French.

[12] All of the county is in the service area of Victoria College.

Donald Trump carried it substantially in the 2020 presidential election.