Set high on the corner of Bonniwell and Cedarburg Roads in Mequon, the extraordinary beauty of the Jonathan Clark House is immediately apparent to all who pass. Surrounded by two and one-half acres of scenic woodland, the house is one of the most architecturally significant historic buildings in southeastern Wisconsin and is a key part of Mequon and Thiensville’s rich history. The beautiful Greek Revival home was built by Clark in 1848, the year of Wisconsin’s statehood, and is on the National Register of Historic Places.  In the 1800’s it was the first of over 20 sites designated as a Mequon Landmark.  Most recently it was home to Dr. Gregory Custer’s dental office.

Originally from Vermont, Clark purchased 80 acres of Mequon land from the United States government in 1839 and another 80 acres in 1843.  He was a prominent early Yankee settler who was instrumental in the development of the government of the Town of Mequon, then the most populated town in Washington County.  He was the first road supervisor and the first supervisor of weights and measures for the area.  In 1843 he was a leader in the development of Mequon’s first public school district as he worked with his father-in-law Peter Turck and their friend William Bonniwell to develop the Bonniwell School.

Peter Turck and his family settled in Mequon in 1837.  He was the 1840 Town of Mequon Census Taker and Jonathan Clark was one of two men who verified the census.  In 1853 Washington County split to make up Ozaukee County and Washington County.

Jonathan died in 1857 at the age of 45 years.  He left behind his wife Mary and eight young children.

For more Clark House history, be sure to visit our Clark House Historian blog.

Click on the following links for additional Historic information:


Photo of Mary Turck Clark

Photo of Mary Turck Clark

and The Mequon – Thiensville Historical Society:  http://www.mthistoricalsociety.org/


Photo of Jonathan Clark.

Photo of Jonathan Clark.


The Friends organization started in 2012 as a Task Force charged with developing a History Museum with 501c3 status.  As the organization formed, Jerry McGinnis, founder of Embassy Homes in Mequon, facilitated the purchase of the property. He bought it from Dr.Gregory and Jean Custer in 2012. While waiting to receive 501.c3 status from the State of Wisconsin, the Friends of Jonathan Clark House, LTD. Board of Directors entered into a partnership with the Mequon Community Foundation. The Foundation provided valuable guidance and fundraising expertise to the Board.  It was dedicated to helping raise start-up funds.
McGinnis jump started the Friends organization by donating $25,000. A generous donation of $25,000 from Sommer’s Automotive of Mequon also provided energy for the project. Additionally, the George and Virgilee (retired Steffen Middle School teacher) Krueck Estate donated $25,000. The Frederick and David Bock Families donation of $30,000 toward the development of important handicap accessible features was a significant and welcome local family commitment.
The Friends are repaying the McGinnis loan through the fundraising efforts of the “Bringing History to Life at the Jonathan Clark House Museum” capital campaign. Family and Single memberships in the Friends of Jonathan Clark House help to sustain the operating expenses of the museum while bringing members of the community together in this historic project.

The first priority of the Friends organization is to raise the funds needed to purchase this precious landmark so that it can be made available for the education and enjoyment of the entire community. The second priority is the development of the handicap accessible features.

Community support is greatly needed!  Read more about how you can help preserve this piece of heritage on the Donate page.


To collect, preserve and share the history of the Jonathan Clark House and the early settlers of Thiensville-Mequon.

 Vision: The Jonathan Clark House Museum will be a self-sustaining, well-integrated community resource.


Learn about the background and history

of the Jonathan Clark House.
Schedule a guided tour!

Read more about the history
of the Jonathan Clark House.

Become a Friends of JCH Member!

Individual and Family Membership Drive going on now! 2017 Renewal or join today!

Click here to see more details.


Haven’t had a tour? The museum is available for individual and small group tours. Contact Museum Director Look at jchmuseum@gmail.com

Historic Jonathan Clark House
            Holiday Open House                                           Saturday, December 2                                        Open House from 9:00 until 1:00

  “Bringing History to Life Campaign” is in full swing!!  Click below to donate & support this effort

Click here to see more details.