Well, everywhere, really.

The Norman Conquest of 1066 wasn't a mass population migration event, but rather a moment of elite replacement. Rather than form their own communities or settlements, the Norman, Breton and French elites who arrived in England with William I instead distributed themselves throughout the country as they claimed, were granted, or ingratiated themselves into the roles of the old English nobility.

The easiest way to see this is to simply look at Domesday Book, an extensive registry of estates throughout England compiled in the 1080s and completed in 1086. You can access a digitalsed Domesday Book via the Open Domesday Project here: https://opendomesday.org/map/

To pick a settlement utterly at random, you'll notice that Nuneham in the Hundred of Headington, Oxfordshire, belonged in 1086 to Richard de Courcy, where in 1066 it had belonged to a Haakon, and the nearby Islip in Kirtlington Hundred belonged to Azelina, wife of Roger de Ivry, whereas in 1066 it had belonged to a Godric and an Alwin.