We know exactly where we are.
Wait. We do? Yep, we promise. Jonson isn't one to leave us hanging.
In the play Cynthia's Revels, Cynthia (a.k.a. the Greek goddess Artemis) calls all her cronies together for a little shindig in the valley of Gargaphia. Echo is invited, and sings her song to the body of water by which she stands. As it turns out, this body of water is the very pool into which Narcissus gazed, falling in love with his own reflection, the idiot.
As we read this poem, we can imagine Echo mourning the loss of her (unrequited) main squeeze on the very site of his death, an eerie, lonely pool in a rural valley in Ancient Greece. We can see the fount, the "herbs and flowers" nearby, and perhaps a "craggy hill" off in the distance.