From Smârdan (on the opposite side from Brăila) to Pătlăgeanca (close to Tulcea), the Danube has only one big flow of water, around which there are an immense number of lakes and small channels.

In the center of the county, there is the Casincea Plateau and the Măcin Mountains—the remains of a prehistorical mountains range (more than 400 million years old), with the greatest height at about 400 m. Agriculture and fishing are the main occupations, involving about 48% of the population.

According to the 1930 census data, the county population was 184,038 inhabitants, ethnically divided as follows: 62.6% Romanians, 12.2% Russians, 10.6% Bulgarians, 2.5% Turks, 1.7% Greeks, 1.3% Germans, as well as other minorities.

In 1930, the county's urban population was 41,632 inhabitants, comprising 64.7% Romanians, 12.8% Russians, 5.5% Turks, 4.4% Greeks, 3.3% Bulgarians, 2.5% Jews, 0.8% Germans, as well as other minorities.

[9] From the religious point of view, the urban population was composed of 87.5% Eastern Orthodox, 5.7% Muslim, 2.6% Jewish, 1.9% Roman Catholic, as well as other minorities.