Sold land that was part of main residence for over 40 years. Made $35000 on the sale. It was not purchased as investment property. How do we list this?

Divided 1.5 acre lot that main residence sits on in order to downsize due to age.  Sold 3/4 acre for $35000.  Was not purchased as investment, lived on it 45 years. Do we have to list it as investment now and pay capital gains?