The Roman Map of Britain Locus Maponi
CISTUMUCI LO[CO] MLbOMI (JRS lviii (1968) 209 slab)
First among the section devoted to the diversa loca, Maponi is echoed in Maporiton (R&C 163) and the modern Lochmaben Locmaban 1166-1296 west of Lockerbie. PNRB equates locus with British *loc- 'lake'. I believe that in this situation locus is best considered as an area of semi-permanent standing water, and depending on the situation perhaps the terms mere or marsh might better fit. In the case of Locus Maponi the explanation may be that the floodplain between Lockerbie and Lochmaben is meant. At an elevation of 50 meters or less, this plain encompasses the junctions of the Kinnel Water, the Dryfe Water and the River Annan. Castle Loch, near Lockmaben, appears to be the remnant of a significantly larger wetland area on this plain.