Spokane, WA
Calgary, Alberta, Canada.
Washington, D.C. is closest to Annapolis, the capital of Maryland.
Baltimore, Maryland
McAllen, TX
I'll assume you mean "Cities in the US", since it's impossible to have "countries in the US". There really aren't any major US cities close to Calgary. Calgary's fairly north of the border in the first place, and on the other side of the border is northern Montana, where there isn't much in the way of big towns. Based on Google Maps, I'd say the closest citites to Calgary would be Spokane WA, Missoula MT, Great Falls MT, or Helena MT. The closest major city would probably be Seattle WA, but it's a bit of a stretch. Sorry if that's not what you're asking.
Annapolis, the capital city of Maryland, is located 29 miles from Washington D.C., the capital city of the United States. Annapolis is the closest state capital.
The area of Downtown Calgary is 1,200,000.0 square meters.
Windsor is on the border between Ontario and Michigan. Its directly across from Detroit, Michigan.
Washington DC is the only city in the United States that is not in a state.
The city the First Bank of the United States is in Philadelphia, Pensylvania.
Unclear question: the city of Calgary is officially the municipality of Calgary.
Pskov is near the border with Estonia in the Baltic States. Smolensk is near the border with Belarus. Chelyabinsk and Omsk are near the border with Kazakhstan. Vladivostok, in the far west, is near the border with China and North Korea.