It's tha phrase "We camped near Lake Arrowhead when we went fishing last year." Subordinate Clause or Independent Clause

Independent clause: "We camped near Lake Arrowhead"

Subordinate clause: "when we went fishing last year."

Explanation:

An independent clause is a group of words that has a subject and a predicate and that conveys a complete message or thought. Therefore, an independent clause can stand alone as a sentence because it is possible to understand it without further information. That is the case with "We camped near Lake Arrowhead."

On the other hand, a subordinate clause is dependent. It too has a subject and a predicate, but it cannot stand alone as a sentence. It needs a main clause to complete its meaning. Imagine someone walks up to you and suddenly says, "when we went fishing last year." You will certain ask them, "When you went fishing last year, what?" There is clearly information and context missing here.

it is an infinitive phrase with a subject.