From Longman Dictionary of Contemporary Englishsouthwesternsouth‧west‧ern /ˌsaʊθˈwestən $ -ərn/ adjective (written abbreviation SW) SGin or from the southwest part of a country or area southwestern Colorado
Examples from the Corpus
southwestern• What puzzles most researchers is just why the area in southwestern Colorado was abruptly abandoned by its ancient citizenry.• His law offices in a small building on the southwestern edge of the city were deluged with calls and visits by reporters.• southwestern Indiana• The northeastern, central, southeastern and southwestern regions of the city showed readings below 250.• The southwestern slope presents a 1,200-foot drop.• Further, the Fugitive Slave Act specifically provided for the rendition of runaways in the northwestern and southwestern territories.• The southwestern United States and California are inundated with illegals.• Phenomenal floods covered thousands of square miles of Labrador and spread like a vast sheet across the central and southwestern United States. 