Grimes Farm and Conservation Center just outside of Marshalltown is a great place to hike and play. Hiking trails provide access to forests, wetlands, prairies, and crop fields. My 6 year old boys love the natural playscape, the storywalk and observation tower.
The observation tower is a 0.6 mile hike from the parking lot. Walk toward the nature center and you'll see a sign pointing in the direction you need to walk. The hike is on wide grass paths.
The natural playscape is a large area with many fun elements including a slide, a music area, a butterfly garden, a swing, a spider web, and a sand play area.
The current storywalk book is Over and Under the Pond. It's along the Boardwalk Trail, starting at the playscape and ending at the nature center.
