Is it considered a sin for a person to live in a land full of ants?

There is no harm for you in building on your land and expelling ants from it, even if that leads to their death, especially if their presence causes harm or nuisance. The prohibition against killing ants applies to those that do not cause harm.

You must rely on Allah the Almighty, adhere to His obedience, preserve your remembrance (dhikr) and supplications (du'a), and put your trust in Him, with the firm belief that He alone is the one who harms and benefits. Be wary of delusions and the whispers of Satan. Merely expelling ants, combating them, and residing in their place does not constitute a sin. Indeed, Uqbah ibn Nafi' and those with him expelled wild animals and pests from the land of Qayrawan and built upon it without considering it a sin.