Professional organizations, in all their variety, are important resources for research, teaching, study aids, scholarship and fellowship opportunities, blog sites — you name it.
The two most important organizations for classicists in the United States are:
Two organizations with valuable resources for undergraduates:
Regional Classics Associations in the US:
Classical Association of New England (CANE)
CAAS (Classical Association of the Atlantic States)
CAMWS (Classical Association of the Midwest and South)
CAPN (Classical Association of the Pacific Northwest)
CCA-S (California Classical Association-South)
California Classical Association Northern Section
Williams is an institutional member of:
Also of interest:
Lambda Classical Caucus, a coalition of queer (broadly construed) classicists and their friends and supporters, with a political and scholarly mission. Lambda is affiliated with the American Philological Association, but its membership is open to all. It publishes Iris.
Classics Associations and Research Institutes, a list maintained by the SCS.