It heads north along a two-lane road through Creston, Greenfield, and Guthrie Center on its way to its northern end at U.S. Route 30 (US 30) near Scranton.

In the late 1970s and early 1980s, the highway south of Iowa 2 was turned over to local jurisdictions.

In southern Creston, the two routes split with US 34 continuing to the east and Iowa 25 heading north along Sumner Street through the western part of town.

West of Summit Lake, the highway turns 90 degrees to the north and passes close to Green Valley State Park.

[3] North of Greenfield, Iowa 25 passes through land equally as rural as that south of the town.

In the northern part of the county, the highway passes Freedom Rock, a large boulder painted every year to honor U.S. veterans and their families.

Just north of Freedom Rock, it meets Interstate 80 (I-80) and US 6 at a diamond interchange adjacent to a golf course.

[7] The concurrency ends as the White Pole Road curves to the southwest while Iowa 25 turns to the north.

[8] North of Guthrie Center, the highway crosses Brushy Creek, a tributary of the South Raccoon River.

Just south of Scranton, it picks up the Lincoln Highway Heritage Byway, a designation it carries to its end.

North of US 30, the roadway becomes County Road N65 (CR N65), which carries the Lincoln Highway Heritage Byway.

[2] A few years later, the highway commission created Iowa 184, which ran from US 34 south to Blockton.