PA-34 pilot reported their left main gear did not indicate down and locked so they landed at a non-towered airport with the left wing overhanging the runway edge over grass field.

Narrative

Airplane had recently come out of annual inspection. Landing gear maintenance had been performed. When the gear was lowered per normal procedures; the gear 'unsafe' light illuminated and all 3 gear down lights did not illuminate. I followed the checklist procedure for 'unsafe gear indication'. The procedure eventually directs the operator to pull the alternate gear extend lever. Once pulled; I only received nose wheel and right main; but the left main gear did not indicate down. Also; the gear unsafe light remained illuminated confirming that the left main light not illuminated was confirmation that the gear was not down and or locked. I simultaneously [requested priority handling] and flew from ZZZ to ZZZ1 for a confirmation from the Tower to see if the gear was down. After a ten mile flight below gear speed; the Tower visually inspected the gear and said it was in the down position. Of course; they could not confirm if it was locked.The Tower Controller appropriately recommended that I land at ZZZ1 as the fire trucks were on station. I elected to return to ZZZ strictly because Runway X has a wide swath of grass alongside the runway. Also; landing on that runway gave me a 15 kt. headwind; thus touchdown speed approximately 60 kts. Unlike ZZZ1; there were no obstructions (runway edge lights or runway marking signs); just approximately 100 feet of wide grass. I maintained my [priority] status throughout the flight; lined up with Runway X with the left wing overhanging the grass but the mains touching down on the left edge of the cement portion of Runway X. Fortunately; the gear did not collapse. I stopped the aircraft straight ahead; shut down; and inspected the gear. The left main was not 'locked'; thus the decision not to taxi was appropriate. I was able to manually push the lock into place and secure the gear to be towed to the ramp.