Gather all ingredients.

Crush 1 cup of chopped peaches in the bottom of a large saucepan. Add remaining peaches and set the pan over medium-low heat.

Bring to a low boil and cook until peaches become liquid with a few bits of peach left, about 20 minutes.

Pour cooked peaches into a bowl, then measure 6 cups peaches back into the pan. Add sugar and bring to a boil over medium heat.

Gradually stir in dry pectin; boil for 1 minute.

Remove from heat and pack jam into hot, sterilized jars, filling to within 1/4 inch of the top. Run a clean knife or thin spatula around the insides of the jars to remove any air bubbles. Wipe rims with a moist paper towel to remove any residue.

Place a rack in the bottom of a large stockpot and fill halfway with water. Bring to a boil and lower jars 2 inches apart into the boiling water using a holder. Pour in more boiling water to cover jars by at least 1 inch. Bring to a rolling boil, cover, and process for 10 minutes.