When delivered on a mobile device, interpretive tours of a locale afford powerful learning experiences. As mobile devices become more powerful, content for these devices that is individualized and location-specific has become more common. In light of this trend, Oregon State University Extension developed a GPS-enabled iPhone tree tour application. This article discusses lessons learned during the design, development, and evaluation of the application and suggests locale-specific instructional content delivered on a mobile device can be an effective instructional approach for Extension educators. (Contains 1 table and 2 figures.)