The most common approach to your situation is point to point wireless. This can be off the shelf stuff from Ubiquiti/D-Link/Whatever, to more specialized products from Aruba, Cambium, etc. Ranges of 1Km and Speeds of 1Gbps are not out of the question at all. You do need line of sight though.
Wireless (or fiber) to link buildings is also a good approach as it eliminates electrical conductivity paths across networks for lightning strikes and power surges.