Porthaven is where the army of Ingary set out from and return to after being defeated. The Porthaven Marshes and the garden at the edge of the Waste are merged into Howl's Secret Garden.
Porthaven itself is a poor village by the sea. The inhabitants of Porthaven include the unnamed girl who was given a luck spell for her father's boat to protect him from rough seas by Michael Fisher and the sea captain who wanted a wind spell. Location's include the quay, and Michael Fisher's old house which he was kicked out of because he couldn't pay the rent.
The Porthaven Marshes is the location Howl caught a falling star as a child, and where Sophie and Michael later attempted to catch a falling star with the aid of the Seven-League Boots.