Here we have a collection of ukulele club websites. Just click on the blue name for a direct link...
If you have club site to share, let me know!

Arizona

Scottsdale Strummers (Scottsdale)

California

Berkeley Ukulele Club (Berkeley)
Fun Strummers Ukulele Band (Modesto)
Hau'Oli Strummers  (San Diego)
High Desert Ukulele Club (Lancaster)
Huntington Beach has several clubs
Napa Valley Flea Jumpers (Napa)
Ukuleles of Paradise (Paradise)
Ukulele Strummers (Stockton)

Connecticut

KookieUkies Ukulele Club of Southern Connecticut (Orange)

Florida

Space Coast Ukulele Club   (Rockledge)
Tampa Bay Ukulele Society (Tampa Bay)

Illinois

Harrison Street Ukulele MeetUp Group (Oak Park)

Indiana

Bloomington Ukulele Club (Bloomington)

Kansas

Kansas City Ukesters (Kansas City)

Nevada

Ukulele Club of Las Vegas (Las Vegas)

New Hampshire

Upper Valley Ukulele Club  (Hanover)

New Mexico

High Desert Sand Fleas (Albuquerque) 

New York 

NYC Ukulele Jam (New York)

Massachusetts

Ukulele Union of Harvard (Harvard)

Minnesota

StrumMN (Twin Cities)
Two Harbors Ukulele Group T.H.U.G. (Two Harbors)

Oklahoma

Tulsa Ukulele Club (Tulsa)

Oregon

Portland Ukulele Association P.U.A. (Portland)

Texas

Austin Ukulele Society (Austin)
Dallas Ukulele Headquarters D.U.H. (Dallas)

Utah 

Utah Ukulele Association (Salt Lake City)

Vermont

The Vermont Ukulele Society (Bristol)

Washington

Seattle Ukulele Players Association S.U.P.A. (Seattle

Wisconsin

Cheez Land Uke Band (La Crosse)
Milwaukee Uke Club (Milwaukee)

Africa

Mercy Ukulele Club (Conakary Guinae,West Africa)

Australia

Blue Mountain Ukulele Club : The Blue Mugs

Canada

Halifax Ukulele Gang H.U.G. (Halifax)
Heritage Uke Club (New Westminster, B.C.)
Toronto Ukes (Toronto)
Vancouver Ukulele Circle (Vancouver)

Sweden

Gothemburg Ukulele Society (Gothemburg)

United Kingdom

People of Lewisham's Ukulele Club - PLUC (London)
Taunton Ukulele Strummers Club (Taunton)
Ukes For Fun (Newcastle-Upon-Tyne)