Where did the Mexican-American War take place?

I want to say near the Rio Grande

Much of it, yes.

https://www.britannica.com/event/Mexican-American-War

Thank you!

You are correct! The Mexican-American War primarily took place near the Rio Grande, which is a river that forms part of the border between Mexico and the United States. The conflict began in 1846, when the United States claimed that the border between Texas (which had recently been annexed by the U.S.) and Mexico was located at the Rio Grande, while Mexico believed the border was further north at the Nueces River.

To get this answer, you can start by researching the Mexican-American War. You can find reliable sources such as history books, articles, or reputable websites that provide information about the war. These sources will provide detailed accounts of the war, including its causes, battles, and locations. By studying these sources, you can gather information about where the war took place and confirm that a significant part of it occurred near the Rio Grande.