(This list was put together by visiting NPCWomen.org, NPHChq.org, the individual (inter)National Websites of each of the NPC/NPHC member sororities, and from Ariesrising's Greek Info Pages. The results can be skewed based on whether you consider Virginia a Southern state (I did), and whether you consider Michigan a Midwestern state (I did). My original statement - that most sororities founded in the north had Monogram style badges - was taken from an article I read in a sorority magazine; I don't remember which one.)
NPC Member Sororities
Midwestern-founded Sororities with Monogram Badges
Theta Phi Alpha
Midwestern-founded Sororities with Shield/Symbol Badges
Pi Beta Phi
Kappa Alpha Theta
Kappa Kappa Gamma
Alpha Chi Omega
Alpha Xi Delta
Delta Zeta
Alpha Sigma Tau
Northern-founded Sororities with Monogram Badges
Alpha Phi
Gamma Phi Beta
Alpha Gamma Delta
Alpha Omicron Pi
Alpha Epsilon Phi
Northern-founded Sororities with Shield/Symbol Badges
Delta Delta Delta
Sigma Kappa
Phi Sigma Sigma
Delta Phi Epsilon
Sigma Delta Tau
Southern-founded Sororities with Monogram Badges
Chi Omega
Southern-founded Sororities with Shield/Symbol Badges
Delta Gamma
Zeta Tau Alpha
Alpha Delta Pi
Phi Mu
Kappa Delta
Sigma Sigma Sigma
Alpha Sigma Alpha
NPHC Member Sororities
(Depending on whether you consider Washington, DC a Southern or Northern City, your answers may differ)
Shield/Symbol Badges
Alpha Kappa Alpha (Washington, DC)
Sigma Gamma Rho (founded in the Midwest - Illinois)
Monogram Badges
Zeta Phi Beta (Washington, DC)
Delta Sigma Theta (Washington, DC)
This should hereby seal my fate as the PRESIDENT of the GC-anonymous group!