Johnson Soils Company, a pioneer in the soil testing and engineering field was founded in 1947 by Carol Johnson, daughter of General H.A. Drum. The company performed laboratory testing for the Army Corps. Of Engineers.  In the 1960’s, John C. Mahle, Sr., a licensed professional engineer in the Army Corps, took over the company and expanded its services to include engineering design and studies. The company was acquired by John C. Mahle, Jr. in 1980 and continued to provide engineering services to design professionals, governmental agencies and land owners. Over the years, its projects spread to the Azores, Indonesia, Greenland and Brazil, which included highway, tunneling and airport projects

Lisa Mahle-Greco, daughter of John C. Mahle, Jr. became President of Johnson Soils Company in 2010. She is now the third generation of Mahle’s to run a geotechnical investigation and design firm. The company continues to expand into construction testing and rock mechanics.