Lawrence Berkeley National Laboratory is a federal laboratory, where on basic, non-classified research is carried out. However, access is restricted to employees (who have a badge), and people with a visitor access.
Ask you host to fill out a visitor access form, at least two days in advance (otherwise, call site access directly, at x4551). The visitor can access the lab either using the shuttle (they need to be emailed a shuttle pass, through the form) or by car (they need to be emailed a parking permit.) Group over ten people need additional forms.
Parking on the hill after 9am can be very difficult, and it recommended to take the shuttle. There are two main shuttle line (main route:blue, alternative route: orange; free, 8am-7pm) that run every ten minutes. Best place to get in the shuttle is on Eastern Shattuck, between Center and Addison (map) or on Oxford street at University (map). The driver should be able to help you with your building.
Before anything, make sure you are not mistaking Lawrence Berkeley National Laboratory for the Lawrence Hall of Science, or Lawrence Livermore National Laboratory — this is a frequent mistake, and while they share the name of Ernest Orlando Lawrence in common, they all are distinct places at distinct locations. Also, while the lab is managed by the University of California, it is independent from UC Berkeley.
The address of the lab is (google map):
Lawrence Berkeley National Laboratory
1 Cyclotron Road
Berkeley, CA 94710
The lab has three entrance : Blackberry gate, Strawberry gate and Grizzly gate; general public access is through the Blackberry gate, which is at the end of Cyclotron road, itself the Eastern extension of Hearst Avenue in Berkeley.
Once at the lab, GPS directions will not work to find specific building. You should refer to the map of the lab to know where you are going. Be careful, the numbering of the building doesn’t follow any obvious logic, as if to challenge your cognitive abilities (here’s an interactive map, for quick look-up)
Main auditorium (Aud50, Aud66, Pers Hall) and main user facilities (ALS, Molecular Foundry, NERSC) are indicated on the map.
Good luck !