The town's spelling, pronunciation and location have changed. Coulsdon originally referred to the area now known as
Old Coulsdon. The name derives from Cuðrædsdun via Cullesdone pre-1130, Culesdone pre-1190, Cullisdon 1242, Culesdene 1255, Colendone c1270, Kulisdon 1279, Collesdon 1288, Cullesdon 1323, Colleston 1324, Coulesdon 1346, Cullysdon 1377, Colynsdon 1428, Colysdon 1439, Collysdon 1563, Cowlesdon 1557, Coulsdon 1597, Cowisden 1604, Couldisdon 1610, Couldesdon 1675, Culsdon 1678, Colsdon 1724. Additional variations include Curedesdone 675, Cudredesdone 675, Cudredesdune 967, Coulsdon 1083, Colesdone 1085, Culesdon 1234, Culisdon 1242, Cudredestreow 1251, Cullesdon 1266, Colesdene 1287, Colesdon 1290, Colesdun 1290, Culesdon 1291, Culesden 1292, Colieston 1324, Coulesden 1326, Coueleston 1332, Colisdon 1344, Culeston 1346, Cullysdon 1377, Cullisdoun 1403, Cullesdoun 1422, Culledon 1424, Colynsdon 1428, Collesdon 1439, Culsdon 1446, Cowlesdon 1539, Collesden 1544, Cowlesdowne 1553, Cullesdoy 1556, Colsdon 1558, Cowlesden 1558, Cullesden 1558, Cowllysdon 1567, Cowisden 1618, Coulsden 1619, Cowsdon 1620, Coolsden 1650, Coulesden 1650, Coilsoun 1655, Coulden 1655. The widely accepted origin of the name is ‘hill of a man called Cūthrǣd’, (from OE pers. name + dūn, a hill). Alternatively the name originates from the Celtic or primitive Welsh "cull", meaning a leather bag, scrotum, bosom, womb or belly. The current town centre appears as Leydown Cross (1738) or Leaden Cross (1800) and Smitham Bottom. In 1905, the parish council, and then the
Post Office renamed "Smitham bottom" as "Coulsdon". The name "Smitham Bottom" has also changed. Smetheden (1331), Smithdenbottom (1536), Smythedean(e)(1548), Smythden Bottom (1588), Smitham Bottom (1719) ==Local government==