Events: Marathon (26.2 miles-4 loops), Half Marathon (13.1 miles-2 loops). Four loops on greenbelts in Kingwood, starting at the Greentree Pool, proceeding to Lake Houston and returning to the Greentree Pool. The course is run entirely on concrete greenbelt trails which are open to the public. Please use caution when crossing streets and be courteous to the residents of the neighborhood. Events: Marathon (26.2 miles-4 loops), Half Marathon (13.1 miles-2 loops). Four loops on greenbelts in Kingwood, starting at the Greentree Pool, proceeding to Lake Houston and returning to the Greentree Pool. The course is run entirely on concrete greenbelt trails which are open to the public. Please use caution when crossing streets and be courteous to the residents of the neighborhood.