Sterilize canning jars and place an aluminum pie tin filled with water on stove. Turn heat to low and add lids and ring bands.
Fill an aluminum canner, fitted with a wire rack, with water to cover canning jars by 2 inches. Cover and bring to a boil over high heat.
Bring a pot full of water over high heat to boil. Dip peaches in boiling water for 30-60 seconds until skins loosen. Dip quickly into a bowl of cold water. Slip off skins, cut in half and remove pits.
Meanwhile, in a medium saucepan over medium heat, add water and sugar and heat until sugar dissolves. Add peach halves once they’ve been skinned, cut in half and pits removed.
Pack jars with peach halves, pit side down, and pour sugar-water solution over peaches, leaving ½” of headspace. Using a clean kitchen towel, wipe rims of jars. Place lids on jars and lightly screw on ring bands. Using a jar lifter, carefully lift jar into boiling water. Repeat with remaining jar. Cover and bring back to a boil. Once water is boiling, set timer for 35 minutes based on an elevation between 3,001-6,000 feet. The heat can be lowered as long as a gentle but complete boil is kept for entire process time.
Turn off heat and wait 5 minutes before removing jars to allow canner contents to settle. Using a jar lifter, remove jars, one at a time, being careful not to tilt jars. Carefully place them directly onto a towel or cake cooling rack, leaving at least 1″ space between jars during cooling. Avoid placing jars on a cold surface or in a cold draft. Let jars sit undisturbed while they cool, from 12-24 hours. Do not tighten ring bands on lids or push down on center of flat metal lid until jar is completely cooled.
Remove ring bands from sealed jars. Put any unsealed jars in refrigerator and use first.
Wash jars and lids to remove all residues. Label jars and store in a cool, dry place out of direct light.