About Us

Get to know Cornerstone Development of S.E. WI., LLC

Wisconsin Condominium Communities

Award-winning Cornerstone Development, headquartered in Sussex, is the preeminent developer and builder of ranch-style Wisconsin condominium communities. For example, Cornerstone’s The Glen at Seven Stones in Sussex, captured the 2015 MBA Achievement Award for Best Development of the Year!

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Founder John Wahlen began building single-story condominiums in the Milwaukee area in 2005, responding to the demographic and cultural changes transforming our society,

Our Wisconsin condominium developers offer ranch-style condo floor plans varying in designs, construction features, and lifestyle. This appeals to retirees, rising young executives and single-again buyers. Each neighborhood condo community includes an on-site clubhouse with a fitness center, community room and outdoor amphitheater, giving residents a carefree lifestyle.


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Call Today (262) 932-4188

Cornerstone Development’s team utilizes over 25 years of engineering, construction, sales and development management with a highly successful track record of neighborhood creation in southeastern Wisconsin. Our Wisconsin condominium developers proudly bring you “The Glens” in the Oconomowoc, Greenfield, Cedarburg and Mukwonago municipalities. Cornerstone Development strives to provide an exceptional community of single story living to create an environment where people enjoy a carefree lifestyle, an enriched life, and a neighborhood offering a remarkable experience.

Contact us now for a free quote on your project