Urban and suburban parks feature this "weed" in unmanicured sunny areas. You can also find it along roadsides, in overgrown fields, backyards, on disturbed soil, and in vacant lots.
Don't confuse this odorless plant with epazote, which smells resinous and is poisonous if eaten in quantity; and don't collect where the soil might be contaminated with toxic nitrates, which it absorbs.