Detroit
The closest border of Canada from Columbus, Ohio is the border with the province of Ontario. Specifically, the closest crossing point would be the Detroit-Windsor border crossing, which is approximately 200 miles north of Columbus. This border crossing is a major international crossing point between the United States and Canada, connecting Detroit, Michigan, and Windsor, Ontario.
Niagara Falls
There is not CLOSE border crossing between Texas and Canada, but you probably go through Detroit.
About 123 km / 76 miles.
Minimum of 2 hrs in good traffic and no delay at the border crossing. Could be twice as long during rush hour and on a busy day at the border crossing.
Buffalo (Buffalo Niagara - BUF) and Toronto (Lester B. Pearson - YYZ) are the two closest major airports to Niagara Falls. There are also regional airports nearby, in Syracuse and on Toronto Island.
260km or 3 hours drive or 161 miles to the closest border crossing is at Carway directly south of Calgary.
The nearest U.S. border crossing at Prescott, Ontario/Ogdensburg NY. Or at Cornwall - Massena or St. Regis, NY.
The closest U.S. border to Ottawa, Canada, is the border with New York State. Specifically, the nearest border crossing is the Thousand Islands Bridge, located about 50 miles south of Ottawa, which connects Ontario with New York. This crossing is part of the larger area known as the St. Lawrence Seaway, facilitating travel between the two countries.
The closest border crossing into Mexico from Las Vegas is at the San Ysidro Port of Entry, located in San Diego, California. This crossing is approximately 330 miles southwest of Las Vegas. Travelers can reach it by taking Interstate 15 south, which connects directly to San Diego. The San Ysidro crossing is one of the busiest land crossings in the world.
There are a few airports close to Detroit. The closest is the Windsor Airport. The next closest is the Detroit Metropolitan Wayne County Airport which is approximately 12 km southeast of the city centre.ANS 2 - Note that Windsor Airport is located in Canada. Although it is close, you have to cross the border to get there from Detroit.