"In May, more than 144,000 people were arrested at the border, according to data from Customs and Border Protection. They were primarily migrants from South and Central America seeking asylum. In August, apprehensions dropped to about 64,000 – the third consecutive month to see a decrease."
This is the result of President Trump, going over the democrats and forcing Mexico to help. The democrats were in the process of trying to legally block Trump from imposing tariffs but Mexico agreed to help before they could do it.
https://www.foxnews.com/politics/on-the-border-officials-see-dividends-from-trumps-deal-with-mexico