where is holden at the present?

In the opening chapters of the novel, Holden is reflecting on the events in his life which have led to his present location. Holden tells us -

'I got pretty run-down and had to come out here and take it easy.'

From this, and him telling us that his brother -

'comes over and visits me practically every weekend'

and will take him home

'next month maybe'

We deduce that Holden has had some sort of breakdown and is in a facility for mental health care.