(Hillsboro, OR)  --  Construction is officially underway on a housing development that's being described as historic.  Ground was broken yesterday on the development that will reportedly be large enough to accommodate 20-thousand people.  The area of what was once farmland is called South Hillsboro, and is bordered by Tualatin Valley Highway, Southwest 209th Avenue, and Rosedale Road.  Officials say construction of houses will begin next year, and people will likely be able to start moving in by 2018.