According to the United States Census Bureau, the city has a total area of 4.4 square miles (11 km2), all land.

[1] The city lies just south of the Arkansas-Missouri state line in northwestern Mississippi County.

Arkansas Highway 77 connects the city with Manila 8 miles (13 km) to the southeast and the state line 4 miles (6 km) to the north at Arkmo (where the road continues as Missouri Route 108 in the direction of Arbyrd, Missouri).

Ecologically, Leachville is located within the St. Francis Lowlands ecoregion within the larger Mississippi Alluvial Plain.

The St. Francis Lowlands are a flat region mostly covered with row crop agriculture today, though also containing sand blows and sunken lands remaining from the 1811–12 New Madrid earthquakes.

[5] The Big Lake National Wildlife Refuge, which preserves some of the bottomland hardwood forest typical of this ecoregion prior to development for row agriculture lies east of Leachville.

As of the 2020 United States census, there were 2,039 people, 971 households, and 654 families residing in the city.

The racial makeup of the city was 85.6% White, 0.3% Black, 0.2% Native American, 0.1% Asian and 1.3% from two or more races.