- Claas
- Claasen
- Claassen
- Clabburn
- Clabby
- Clabots
- Clabough
- Clace
- Clacey
- Clack
- Clackers
- Clackson
- Clacy
- Clad
- Claden
- Cladera
- Clae
- Claerhout
- Claes
- Claesen
- Claesens
- Claeson
- Claessen
- Claessens
- Claesson
- Claeys
- Claffey
- Claffy
- Claflin
- Clagett
- Clagg
- Claggett
- Clague
- Claiborn
- Claiborne
- Claiden
- Clail
- Clain
- Clairac
- Claireaux
- Clairet
- Clairmont
- Clairmonte
- Claisse
- Clak
- Clammer
- Clamp
- Clampett
- Clampin
- Clampit
- Clampitt
- Clanahan
- Clance
- Clancy
- Clandillon
- Claney
- Clanmorris
- Clans
- Clanton
- Clanwilliam
- Claparede
- Clapcich
- Clapcott
- Clapes
- Clapham
- Claphan
- Clapison
- Clapper
- Clapperton
- Clappison
- Clapshaw
- Clapson
- Clapton
- Claque
- Clar
- Clara
- Clarabut
- Clarc
- Clarck
- Claremont
- Clarence
- Clarendon
- Claret
- Clarey
- Clarges
- Clarice
- Clarici
- Claricoates
- Claricoats
- Clarida
- Claridge
- Clarin
- Claringbold
- Clarion
- Claris
- Clarisse
- Clariza
- Clarizio
- Clark
- Clarke
- Clarken
- Clarkes
- Clarkeson
- Clarkson
- Claro
- Claros
- Clarr
- Clarricoates
- Clarridge
- Clarry
- Clarson
- Clart
- Clary
- Clas
- Clasby
- Clase
- Clasen
- Clasing
- Clason
- Class
- Classe
- Classen
- Classey
- Classique
- Classon
- Classpeter
- Clater
- Claton
- Clattenburg
- Clatworthy
- Claud
- Claudel
- Claudet
- Claudi
- Claudin
- Claudine
- Claudino
- Claudio
- Claudius
- Claudon
- Claudot
- Claus
- Clause
- Clausen
- Clausing
- Clausner
- Clausnitzer
- Clauss
- Clausse
- Claussen
- Clausson
- Claustres
- Clauw
- Claux
- Clauzel
- Clauzelma
- Clave
- Claveau
- Clavel
- Clavell
- Clavelle
- Claver
- Claveras
- Claveria
- Claverie
- Clavering
- Clavero
- Clavery
- Clavet
- Clavey
- Clavier
- Clavijo
- Claw
- Clawley
- Clawson
- Claxson
- Claxton
- Clay
- Claybon
- Clayborn
- Claybourn
- Claybourne
- Claybrook
- Clayburn
- Claycomb
- Clayden
- Clayfield
- Clayhills
- Clayman
- Claymore
- Claypole
- Claypool
- Claypoole
- Clays
- Clayson
- Clayton
- Claytor
- Clayworth