A system and method for intracranial access is disclosed. In particular, a drill stop is shown providing a way to control the penetration of a drill bit as an access hole into the brain is being formed. Access to a desired location is achieved using a catheter guide device. Also disclosed is a mechanism by which multiple diagnostic and treatment devices can be placed at a desired location in brain tissue without the need for more than one access hole. A drainage catheter is disclosed with a mechanism to allow both drainage and to allow intracranial pressure measurement.