One segment of 30.8 miles (49.6 km) runs from U.S. Route 278 (US 278) in McGehee north to US 165 at Back Gate.

A third segment of 95.8 miles (154.2 km) runs from US 49 at Walnut Corner north to the Missouri state line.

[3] The route continues across US 65/US 165 and exits town in a northeastern direction, passing McGehee High School.

Continuing north, Highway 1 ceases following the railroad at Watson and runs west to US 165 at Back Gate, where it terminates.

The route runs east through St. Charles before entering Monroe County, where it meets Highway 1S.

[8] At the corner, Highway 1 turns north past the Richardson-Turner House and enters Lee County.

[10] Further north, Highway 1 passes Lee County Senior High and becomes four lanes briefly until Forrest City.

[13] The highway continues north to Vanndale and Cherry Valley before entering Poinsett County.

[13] The route passes through marshes in southern Poinsett County before entering Harrisburg.

[1] As cities have grown, bypasses have become necessary, and the former downtown alignments of Highway 1 have become the business routes discussed here.

[11] DeWitt, Marianna, Vanndale, and Cherry Valley all have business routes of less than 3.0 miles (4.8 km).