Beginning in 2009, club scoring awards at Nationals have been divided into two separate categories: Regional and Local. A formal description of the two club categories is below (104.5.6B &  from page 35 of the 2013 USMS Rule Book):
(1)Regional - For competition at national championship meets, a Regional Club consists of a club made up of those swimmers who represent a club at nationals, but at competitions within their LMSC, they compete for an entity or subgroup (such as a workout group) that is different than the one they compete with at nationals.
(2) Local - For competition at national championship meets, a Local Club consists of a club that does not qualify as a Regional Club.
Based on these definitions, the following scoring categories will be in place for 2013 Nationals:
AKMS - Alaska Masters Swim Club
ARIZ - Arizona Masters Swim Club Inc
CMS - Colorado Masters Swimming
FACT - Florida Aquatic Combined Team
GAJA - Georgia Masters
HMS - Hydropower Masters Swim Club
IAMA - Iowa Masters
IM - Illinois Masters
MICH - Michigan Masters
MM - Montana Masters
NCMS - North Carolina Masters Swimming
NEM - New England Masters Swim Club
NIAG - Niagara District Masters
NMMS - New Mexico Masters
OREG - Oregon Masters
PSM - Puget Sound Masters
SKY - Swim Kentucky Masters
SMS - Southern Masters Swimmers
SWOM - Southwest Ohio Masters
UTAH - Swim Utah
WMAC - Wisconsin Masters Aquatic Club
WMSC - Wyoming Masters Swimming Club
Local Clubs: all other registered USMS clubs.
According to the USMS Rule Book the Championship Committee shall publish this list no later than February 15 of each year. Please note clubs may contest their designation or the designation of another club by filing an appeal with the chair of the Championship Committee (Jeff Roddin, firstname.lastname@example.org) at least 45 days prior to the national championship meet (those deadlines would be March 25 for Indianapolis and June 23 for Mission Viejo).
USMS Championship Committee Chair