Interstate highways in Iowa
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Interstate 35
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
Entrance photos

Counties: Worth, Cerro Gordo, Franklin, Wright, Hamilton, Story, Polk, Warren, Clarke, Decatur
Cities along route: Clear Lake, Latimer, Coulter, Ellsworth, Randall, Story City, Ames, Huxley, Ankeny, Des Moines, Johnston, Urbandale, Grimes, Clive, West Des Moines, Cumming, Bevington, Osceola, Van Wert, Decatur, Lamoni

Exit lists:
  • 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

  • Multiplexes:
  • 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)
  • History
  • 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
  • Notes
  • 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. The six-lane segment in Ankeny was extended northward two miles to 36th Street in December 2020 and will be extended to IA 210 at Huxley by 2026. Also, the segment through Urbandale and Clive is programmed to be widened to eight lanes from 2025 through 2027 as part of the reconstruction of the interchange with US 6/Hickman Road into a diverging diamond interchange.
  • In 2017, the Iowa DOT released a preliminary design for a "full-build conceptual layout" of the East Mixmaster that reconstructing almost all exit ramps. As it stands, replacement of the left exit from eastbound I-80 to northbound I-35 at the East Mixmaster system interchange with a new flyover ramp began in 2022 and is expected to be finished in the fall of 2024. This project also involves new ramps between eastbound I-80 and westbound I-235 (opened December 1, 2023), and between westbound I-80 and northbound I-35 (to be completed in the fall of 2024).
  • Meanwhile, work to replace the loop ramp from I-35 south to I-235 west and the ramp where I-80 splits from I-35 at the West Mixmaster system interchange is programmed for 2027 and 2028.
  • Refer to the Iowa DOT's Des Moines Area Interstate Projects page for more information about the projects mentioned above.
  • 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.(Terminus photos)
  • 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.

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    © 1998-2024 by Jason Hancock / Last updated June 6, 2024