That's very impressive! How do the relative elevations compare? I'm guessing it's either line-of-sight or something close to that?
I live in a hilly area, and I was getting great range up until too much hill got between the Tx and Rx. It did better than LOS, though. It was picking up a lot of signals bounced off buildings that it couldn't have gotten if it were purely LOS.
When the signal "absolutely, positively has to get there," LoRa is a great choice, even for shorter distances like around the house. The incremental cost is reasonably low considering what you get, and it comes with a top notch FSK radio similar to the RFM69 in case you want to run at higher bitrates. Because of the higher Tx time, though, for battery applications I tend to think of LoRa as an awesome fallback option in case the primary FSK communications aren't getting through.