US Space Command, which currently is responsible for monitoring the heavens, is tracking some 41,000 pieces of space junk bigger than 10 centimeters … 
… NASA, tracks over 25,000 objects larger than 10 cm in LEO, the estimated number between 1 and 10 cm in diameter is 500,000. The amount of particles bigger than 1 mm exceeds 100 million.It’s becoming even more crowded by the debris fields of anti-satellite (ASAT) tests. Russian and Chinese ASAT test debris accounted for 20% of orbital collision warnings in 2022.
… the 700 to 900 kilometer band of LEO, a region that is increasingly crowded due to advent of mega-constellations such as SpaceX’s Starlink communications satellites. That orbital altitude also is being used by the Space Development Agency for its planned Transport Layer of 300 to 500 high-speed, high-volume communications birds.LEO confers interesting capabilities and limitations.
Unlike geosynchronous satellite, satellites in LEO have a small field of view and so can observe and communicate with only a fraction of the Earth at a time. This means that a network (or "constellation") of satellites is required to provide continuous coverage. Satellites in lower regions of LEO also suffer from fast orbital decay and require either periodic re-boosting to maintain a stable orbit or launching replacement satellites when old ones re-enter.As a reference and point of interest, the 20-Feb-2008 shootdown of satellite USA-193 by a SM-3 Standard missile launched by USS Lake Erie occurred at an altitude of around 250 km (155 miles).