In late September of '21, my wife and I experienced the joy of this awesome, five-star urban trail on a weekday morning. Even though it's completely within the Sioux Falls city limits, you'd hardly know it except for the occasional sounds from distant autos, the even more occasional sounds from the airport flight path, and the beautiful buildings you glimpse as you pass through an exceptionally quiet downtown. For the most part you're enveloped within the serenity of trees, parks and greenways, surrounded by wide open spaces and golf courses, or hearing the thunderous noise of the falls at Falls Park.
Even though it's called Sioux Fall Bike Trails, we stuck to one trail: the twenty mile loop that follows the two forks of the Big Sioux River and essentially encircles much of the city. We started our ride at Farm Field Park, a popular starting point for the many walkers and joggers utilizing the trails, and proceeded in a counterclockwise direction. Thank goodness for my investment in the Rails To Trails Link app! There were a couple of instances where we unsure which fork in the trail to take, and the app kept us on the right path!
With the exception of some rough patches of asphalt and two plus miles on a gravel road due to construction on the main loop trail out near the airport, most of the trail was excellent, wide, flat, and provided smooth riding.
WARNING: Besides the temporary construction detour, be aware of the steep climb just beyond the falls up the side of a dam. If not for my sixty-three year old wife's Swytch pedal assist, she would have been walking her bike up that steep grade. To avoid that, consider taking the loop in a clockwise direction.
All in all, the trail lived up to it's five star billing and was worth the 2,000 mile drive from SoCal to check off another state bike ride on our bucket list! We experienced the beautiful falls, sculptures, wildlife, architecture, arriving and departing jets, trestles, bridges, levees, zoo animals, river views, trees, and the super friendly walkers, joggers, and bike riders of Sioux Falls.
( By the way, so many previous reviewers were rough on the part that goes around the airport, but it was especially quiet, peaceful, and serene out there except for the infrequent jet landing or taking off. I enjoyed the views from the levees and solitude away from the town as much as riding within it.)

I did the trail from Pipestone to Woodstock. I attempted to continue to the county line, but the final 2 miles leaving Woodstock isn't maintained. It was knee high weeds. Still, a really fun trail mixed with mostly asphalt, some gravel, and a little grass. My ride was 22 miles round trip.
I was riding a drop bar gravel bike with 40mm slick tires which was perfect for the trail. The first asphalt section is similar to a highway shoulder...mostly smooth with some cracking. The second asphalt section is very smooth. Next is mostly flat gravel which turns into grass through the park in Woodstock.
I enjoyed the trail, and will visit again. A fun ride!