Centennial Park is located near the Union County Fairgrounds and Union County Historical Park, home of one of the community's four model dinosaurs, behind Union County General Hospital. Picnic Tables on the lawn of the Clayton-Union County Chamber of Commerce office are also convenient. Clayton has a marked bicycle route through town extending east on Hwy 56-412 to a historic marker about two miles west of the city limits. Clayton is visited by an unusually large number of transcontinental bicyclists each year. It is also on the route of a cross-country bicycle endurance race.
Motorcyclists also abound.
A jogging and scientific exercise course is maintained by the Clayton Lions Club at the municipal airpark, located east of the golf course and between the two baseball diamonds. Birdwatching is one of the more popular pastimes in this area. Union County has participated in the annual Audubon Christmas Bird Count. Watchers have documented well over 200 species which are seen with some regularity in the region.