I read this all the time. I clock it at 13.6 miles starting from the river at Nelson Island going down to Olathe to the South. This Trail also connects to the Mahaffey trail system.

I think the trail is longer than what's listed here. Runs from Noland Rd to Sibley Mo. Very scenic.

Been on ICT since the early 2000s. The park and rec of OP needs to serious repave vast sections of asphalt on the trail where the nearby tree roots have caused significant damage to the asphalt. No reason super rich JOCO can ignore the neglect of the trail.

Cool trail that is flat, quiet and goes a long way. Often not a lot of people.

Our quest to ride in every state in America landed us in Vassar, Kansas, a one-horse town about 30 miles south of Topeka, at a trailhead for the Flint Hills Nature Trail. Thankfully, we’d read that it was near a grain silo, otherwise, we might have missed the small dirt clearing we used as a parking lot.
The seventh longest rail-trail in America, the Flint Hills Trail stretches 117 miles across eastern Kansas on what used to be the Missouri Pacific Railroad. Today, it is a crushed stone path with occasional pieces of shale and deeply rutted soft dirt. Riding was slow and bumpy the first several miles and we had to keep a tight grip on our handlebars. The trail was straight as an arrow and flat as a pancake, although the rolling Flint Hills surrounded us. We’d read that there were turkeys and bobcats in the area, the latter of which we may have seen earlier in the day when what we thought was a large, healthy fox darted across the highway. Actually, the only wildlife we encountered while biking were very loud flying insects that reminded us of the cicadas that plague the mid-Atlantic every 17 years.
The trail was lined with scrubby cedars and other trees that formed a narrow screen between us and the farmland on either side. These provided some shade on what otherwise would have been a scorching ride in the summer sun. About every mile, we passed through a gateway with a post on either side, that looked, from a distance, like approaching figures. In fact, we only passed one other bike and two pedestrians during our two-hour ride. The trail widened and improved after we passed through a gateway onto a very broad two-lane roadway with well-packed dirt and cinder.
Award-winning beers awaited us at a brewery outside of Topeka.

The Line Creek has probably the best trail surface we've ever been on. Very nice ride which has curves, some hills and great scenery. This is a multiuse trail for pedestrians, bicycles and cars for a short section. It travels through mostly wooded sections which offers some shade as well as a wind block on those windy days.
The lack of trail signage was an issue and there were a couple of times that required using a GPS to find reconnect points. There are a few small businesses and also the Argosy Casino that could really benefit if they helped mark and promote the trail! We'll probably come back during our next road trip on the I-35.

We started at the Berkley Riverfront Park because there is construction at Bally's KC Casino. Very nice trail with great features such as the elevator and wooden bridge. After this point the trail was very difficult to navigate which proceeded on rough broken pavement through a heavy industrial area. There were several construction projects going on (bridges) leaving road debris.
This trail needs signage and the unfamiliar rider should not need to rely upon GPS. A good surface cleaning would also help.

Stopping every block for traffic was frustrating along with the two block stretch through parking lots with no clear idea where the trail picked back up. Lot's of folks walking and could be a nice trail but a lot of the curbs have either sunk or the gravel leading to them has washed away. Very rough ride on a street bike. Drainage appears to be a significant issue though some of that is just due to saturation after a snow. Might try it again when it's dryer. Lots of Pokestops if you do that.

Asked Ottawa Bike Shop owner which direction to go on either trail. He suggested eastbound so thats where we headed. Only rode 5 miles before heading back to Ottawa. Great trail, a little wet but very pleased how our fat tire ebikes performed in these conditions, just perfect. This part of the trail almost all canopied, very nice. Definitely going to come back, go further.