Conner Mantz Shatters 23-Year American Marathon Record in Historic Chicago Run

American distance runner Conner Mantz made history at the 2025 Chicago Marathon. He smashed a national record that had stood for 23 years. The 28-year-old finished with an astonishing time of 2:04:43.

This performance officially breaks the previous American record of 2:05:38 set by Khalid Khannouchi in 2002. According to reports from Runner’s World, Mantz executed a near-perfect race strategy to achieve this monumental feat.

Flawless Execution in Ideal Conditions

Mantz capitalized on cool, calm weather in Chicago. He maintained remarkably even splits throughout the 26.2-mile course. His consistency was key to sustaining the record-breaking pace.

He passed the halfway mark in 1:02:19. His second half was only five seconds slower. This negative split strategy demonstrated exceptional fitness and pacing control.

A Career Built for This Moment

Mantz has been on a steady ascent in the marathon world. He previously ran a 2:05:08 at the 2025 Boston Marathon. That time was not eligible for the official record due to the Boston course’s layout.

His focus then shifted squarely to Chicago. He bypassed the World Championships to prepare. This single-minded dedication paid off with the historic result.

A Thrilling Race to the Finish

The men’s race was fiercely competitive from the start. Uganda’s Jacob Kiplimo pushed a blistering world-record pace early on. Mantz ran smartly within the lead pack.

He remained composed as the pace intensified. In the final miles, he battled Kenya’s Alex Masai for third place. Masai ultimately edged him out, but Mantz’s fourth-place finish was secondary to the record.

He crossed the line with a triumphant smile. The clock confirmed what he already knew. A new era for American marathoning had begun.

The new American marathon record of 2:04:43 firmly places Conner Mantz among the global running elite. His historic performance in Chicago redefines what is possible for U.S. distance runners on the world stage.

Info at your fingertips

What was the previous American marathon record?

The previous record was 2:05:38. It was set by Khalid Khannouchi at the 2002 London Marathon. That record had stood for over two decades.

Why did Mantz’s faster Boston time not count as the record?

The Boston Marathon course is point-to-point and has a net elevation loss. World Athletics and USATF do not recognize records set on such assisted courses. This makes Chicago, a looped and flatter course, ideal for record attempts.

Who won the 2025 Chicago Marathon?

Uganda’s Jacob Kiplimo won the race with a stunning time of 2:02:23. He was followed by Ethiopia’s Tamirat Tola in second place. Kenya’s Alex Masai finished just ahead of Mantz in third.

What does this mean for American long-distance running?

Mantz’s record is a huge boost for the sport in the United States. It breaks a significant psychological barrier. It inspires a new generation of American runners to compete on the global stage.

What is Conner Mantz’s next major race?

Mantz is now focusing on the USATF Cross-Country Championships in December. A top finish there would qualify him for the World Cross-Country Championships in Tallahassee, Florida, in January 2026.

Trusted Sources: Runner’s World, Reuters, FloTrack