In the US state of Iowa, Interstate 29 (I-29) is a north–south Interstate Highway which closely parallels the Missouri River. I-29 enters Iowa from Missouri near Hamburg and heads to the north-northwest through the Omaha–Council Bluffs and the Sioux City areas. It exits the state by crossing the Big Sioux River into South Dakota. For its entire distance through the state, it runs on the flat land between the Missouri River and the Loess Hills. I-29 was built in sections over a period of 15 years. When there was a shortage of male workers, female workers stepped in to build a section near Missouri Valley. Between Council Bluffs and Sioux City, I-29 replaced U.S. Highway 75 (US 75) as the major route in western Iowa. As a result of I-29's creation, US 75 south of Sioux City was relocated into Nebraska. Route description I-29 enters Iowa south of Hamburg. The Interstate heads northwest, where it meets Iowa Highway 333 (Iowa 333) at a diamond interchange. From Hamburg, I-29 continues to the northwest for where it meets Iowa 2 east of Nebraska City, Nebraska. North of the Iowa 2 interchange, the Interstate straightens out to the north; interchanges serving Percival, Thurman, and Bartlett are spaced out every . At the US 34 interchange near Glenwood, I-29 is joined by US 275. North of Glenwood, I-29/US 275 continue north toward Council Bluffs. Near Lake Manawa, US 275 splits away from I-29 at the Iowa 92 interchange. The Interstate meets I-80 north of the split. The two Interstates head west together through southern Council Bluffs for on separate carriageways. Just before I-80 crosses the Missouri River into Nebraska, I-29 immediately turns to the north. to the north is a modified Y interchange with US 6 and the eastern end of I-480. North of Council Bluffs, I-29 passes the eastern terminus of I-680 near Crescent. I-29 travels north for before intersecting with the western terminus of I-880 near Loveland. I-29 continues north for to Missouri Valley, where it intersects US 30. North of Missouri Valley, the Interstate turns to the northwest toward Modale and then straightens out again south of Mondamin, where I-29 meets the western end of Iowa 127. From Mondamin, it travels north for to the Iowa 175 interchange at Onawa, passing Little Sioux and Blencoe. North of Onawa, I-29 continues northwest for toward Sloan, where it meets the western end of