12 Mile Circle. The northern boundary of the State of Delaware (where it meets Pennsylvania) has a radius of 12 miles from the spire of the New Castle...

Put the prism on the threaded end of a 4' range pole section. Add however many 4' sections of the range pole that you need, then attach range pole se...

Tacks in hubs & spikes in dirt. Yeah that plumb bob is dinged up.