Originally an isolation hospital, Send became a prison in 1962 when it opened as a junior detention centre. In 1987 it was reclassified as a category C adult male training prison and by 1999 the prison had been completely rebuilt and had changed its role; it now operates as a closed female training prison.
Send houses a 20-bed addictive treatment unit, an 80-bed resettlement unit and the only female prison therapeutic community with a capacity of 40. It also has a 20-bed psychologically informed physical environment (PIPE) community with approval to expand to 40 beds.
- A wing: 40 cells over two floors, providing the PIPE unit
- B wing: 38 cells over two floors and identified as the induction wing
- C wing: 40 cells over two floors
- D wing: 10 cells, each doubles for prisoners on Rehabilitation for Addicted Prisoners Trust (RAPt) programme
- E wing: Resettlement unit, accommodating 40 cells
- F wing: Resettlement unit, accommodating 40 cells
- J wing: 64 cells over two floors including 32 beds dedicated to the therapeutic community.