1958: The Marshall County Conservation Board (MCCB) was authorized by a vote of County residents to "acquire, develop, maintain and make available to the inhabitants of the county public museums, parks, preserves, parkways, playgrounds, recreation centers, county forests, wildlife and other conservation areas; to promote the orderly development and conservation of natural resources; and to cultivate good citizenship by providing adequate programs of public recreation."
1964: Leonard and Mildred Grimes purchased the farm from Jon Batesole and began to restore the land using conservation practices and sustainable farming. — More than 350 sixth grade students from Marshalltown began visiting the Grimes Farm annually as part of their conservation unit, a field trip that has continued every year since then.
1991: Leonard and Mildred Grimes began to donate 160+ acres of land to the Marshall County Conservation Board and the Iowa Natural Heritage Foundation.
1992: Fisher Controls of Marshalltown awarded a $25,000 gift to the Nature Center projects.
1993: The architectural firm TSP of Marshalltown was retained to design the Nature Center.
1995: A pedestrian bridge and footing was built, spanning the woody ravine to the west of the parking area.
1997: A Citizens Advisory Committee was formed to help the Board review and evaluate plans developed. An access road was constructed.
1998: Eagle Scout candidates created a half-mile handicapped-accessible trail through forest, wetland, and prairie environments.
1999: Earth berms were reshaped; bus parking was enhanced; a 40-foot hexagonal shelter house was built; three wetlands were excavated; and 10 acres of prairie grasses and flowers were planted.
2000: A landscape plan was implemented by the Marshalltown Garden Club; a fund-raising feasibility study began.
Planning continues for the American Discovery Trail that will link the Atlantic and Pacific Oceans by bike trail. The trail will traverse directly through the Grimes Farm in 2002.