The county was located in the central-eastern part of Greater Romania, in the south of Moldavia.

Tecuci County was initially divided administratively into three districts (plăși):[1] Subsequently, the territory was reorganized into five districts: According to the 1930 census data, the county population was 156,405 inhabitants, 94.9% were Romanians, 2.0% Gypsies, 1.8% Jews, as well as other minorities.

From the religious point of view, 96.3% were Eastern Orthodox, 1.9% were Jewish, 1.6% were Roman Catholic, as well as other minorities.

In 1930, the county's urban population was 17,172 inhabitants, 86.5% Romanians, 8.9% Jews, 1.1% Hungarians, 1.0% Gypsies, 0.8% Germans, as well as other minorities.

From the religious point of view, the urban population was composed of 88.3% Eastern Orthodox, 9.2% Jewish, 1.3% Roman Catholic, 0.5% Lutheran, as well as other minorities.