Length in Iowa: 219 miles/352 kilometers
Northern terminus: Minnesota state line south of Albert Lea, MN
Southern terminus: Missouri state line south of Lamoni
Counties: Worth, Cerro Gordo, Franklin, Wright, Hamilton, Story, Polk, Warren, Clarke, Decatur
Cities along route: Hanlontown, Clear Lake, Swaledale, Thornton,
Latimer, Williams, Ellsworth, Randall, Story City, Ames, Huxley, Elkhart, Ankeny,
Des Moines, Johnston, Urbandale, Grimes, Clive, West Des Moines, Cumming,
Martensdale, Bevington, St. Marys, St. Charles, Osceola, Van Wert, Decatur
From US 20 northward to the Iowa/Minnesota state line
From US 20 to I-80 near Des Moines
From I-80 southward to the Iowa/Missouri state line
28 miles with IA 27, between the Minnesota state line and exit #190 (US 18) south of Clear Lake; this includes a 3½-mile triplex with US 18 between exits #190 and #194.
14 miles with I-80, from exit #73 in West Des Moines to exit #87
in Des Moines (exit numbering follows that of I-80)
September 21, 1958: First segment, from Douglas Avenue (now in Urbandale) to
County Road Q (now G14) west of Cumming, opened (partly with I-80)
October 5, 1958: Segment between County Road Q and IA 92 opened. The junction with IA 92
was originally a four-way stop, as right-of-way issues with a railroad initially prevented
interchange construction, but an interchange with IA 92 finally opened in 1960.
November 9, 1958: Segment between Douglas Avenue and Merle Hay Road (IA 401) opened (with I-80)
November 26, 1958: Segment between IA 92 and County Road S (now R35) north of Osceola opened
November 28, 1959: Segment between Merle Hay Road and US 69 north of Des Moines opened (with I-80)
August 30, 1960: Segment between current County Road R35 and US 34 opened
November 17, 1960: Segment between US 69 and the future "east mixmaster" with I-235 (with I-80) opened
November 11, 1965: Segment from US 30 in Ames to I-80 opened
December 6, 1967: Segment from US 20 near Blairsburg to US 30 opened
December 17, 1969: Segment between US 34 and IA 2 opened
December 2, 1970: Segment between IA 2 and US 69 (at the Missouri state line) opened
August 7, 1971: Segment between IA 9 and IA 106 near Mason City opened
November 30, 1972: Connection from US 69 into Missouri opened
December 12, 1972: Segment from Minnesota state line to IA 9 opened
November 7, 1975: Last segment, between IA 106 and US 20, opened
On September 1, 1965, the alignment of I-35 was changed at the urging of Mason City
civic leaders. It had previously been scheduled to follow US 69 all the way
north of Des Moines, but it was then moved closer to Mason City to parallel
US 65 instead. This created the infamous "Mason City Diagonal" through
Wright and Franklin counties, which farmers in the area objected to because of fears
that diagonally-shaped farms would reduce productivity. Litigation delayed I-35 for
several years; in November 1972, a federal judge in Des Moines rejected a lawsuit
that a group of farmers had filed against the state, allowing the last segment of the last
original 1956 Interstate in Iowa to open in 1975.
Another shift in I-35's alignment, the bend between Story City and Ames, was done to accommodate Ames Lake, a reservoir that was first proposed in 1965 but scrapped by the Army Corps of Engineers in 1987. A scenic overlook exit was built along southbound I-35 because of the plans for the lake; this exit is now signed as a "Prairie Area".
Widening of I-35 from four to six lanes between the western split of I-80 and IA 5 in West Des Moines was completed in May 2015. Widening of the I-35/80 multiplex from four to six lanes was completed by the end of 2000, while the segment from Ankeny to the I-80/235 "East Mixmaster" junction was widened to four lanes by the end of 2003.
Business Loop 35
Ames: This route was designated in 1995 by officials of their
Chamber of Commerce and was approved by AASHTO on October 27, 1995. The route runs
along US 30 from I-35 (exit #111) to the Duff Avenue (US 69) exit; then
it follows US 69 (Duff Avenue, Lincoln Way, and Grand Avenue) northward
through the city before following 13th Street eastward back to I-35.
Clear Lake: A second I-35 business loop was approved by AASHTO on April 17, 1999,
following 4th Avenue South, 8th Street, and US 18 between I-35 exits 193 and 194; thanks to Mark Hasty for originally pointing this out. (Terminus photos)
A third business loop was proposed for Lamoni but was denied by AASHTO on November 15, 1997. It would have followed US 69 between the Missouri state line and I-35 exit 4.