> For the complete documentation index, see [llms.txt](https://zillion.gitbook.io/iredistrict/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://zillion.gitbook.io/iredistrict/lock-and-run.md).

# Lock Districts

In the toolbar above the map, there is a locking tool.  The **lock** function in iRedistrict gives the user an option to lock some districts of an existing plan while continue to optimize for the unlocked districts. 

Click the locking tool and then click the district on the plan to lock these districts. Then click "run" to rerun redistricting. The new plans will preserve the locked districts and redraw other districts.

![](/files/-MJ031oMqHuJnrvZUOMn)

When locked, a district will visually change to a darker shade. To release the lock button, click on the lock icon again.

![](/files/-MJtCFv2yJtHxWuHNOfa)