Lost Sectors are some of Destiny 2's most distinctive features, while their main purpose (outside of occasional quest appearances) was to make them a quest requirement, a straightforward bounty completion, or a way to farm enemies.
Bungie provided a new way to acquire Exotics by farming a Legend or Master version of Lost Sectors. These activities have specific Power Level caps, just like Nightfalls with the same difficulty, and by accomplishing them solo you may win an Exotic in a specific slot, for example.
The Quarry is located in the East Midlands, just a short walk from the Sunken Isles landing zone and to the Lost Sector itself. (like Season of Plunders Cryptic Quatrains III), here's how to locate this Lost Sector.
In Destiny 2, how do I find the Quarry Lost Sector?
The Quarry is within the EDZ, and it's relatively easy to find it. Open the EDZ and go to the top left, looking for the Sunken Isles region on the northwestern part of the destination. When you land, follow the trail that has an antenna to reach the Quarry entrance on your left.
If the Quarry is the daily Lost Sector, you may also use the several sparrows parked nearby as an indication of its location. They should appear when you get closer to the hill with the antenna.