If you thought Baltimore-Washington International Marshall Airport felt a little more crowded recently, you’re right: The airport set a record with more than 22 million passengers last year.

“BWI Marshall Airport’s continued success is great news for residents, businesses, and travelers in Maryland and throughout the entire National Capital region,” Gov. Martin O’Malley (D) said in a statement announcing the record.

The airport saw more than 455,000 additional passengers compared to 2010, which had previously held the airport’s single-year record. The 22,391,785 passengers who flew through Charm City included 2.2 million who used BWI in July, setting an airport record for most passengers in a month.

More than half of BWI’s travelers used Southwest Airlines in 2011, with more than 12.5 million passengers flying the airport’s leading carrier. AirTran was the second leading carrier.

The impact of the Southwest-AirTran merger was particularly noticeable at BWI when AirTran Airways moved to the Southwest Airlines terminal in November. The merger gave Southwest control over roughly a third of the Washington region’s air travel.

This week, Southwest started offering flights between BWI and the city-state that is Atlanta’s airport. Next month the airport will begin offering direct flights between BWI and Cuba.