Also the Chicago Deep Tunnel system is pretty massive
"Phase 1, the creation of 109.4 miles (176.1 km) of drainage tunnels ranging from 9 to 33 feet (2.7 to 10.1 m) in diameter, up to 350 feet (110 m) underground, was adopted in 1972, commenced in 1975, and completed and operational by 2006."
"Phase 1, the creation of 109.4 miles (176.1 km) of drainage tunnels ranging from 9 to 33 feet (2.7 to 10.1 m) in diameter, up to 350 feet (110 m) underground, was adopted in 1972, commenced in 1975, and completed and operational by 2006."
https://en.wikipedia.org/wiki/Tunnel_and_Reservoir_Plan