Trying to recall name of novella originally printed in Isaac Asimov's Science Fiction Magazine. The story involved a character traversing a world that consisted of a single peninsula bounded by two seas.
It was Kim Stanley Robinson's "A Short, Sharp Shock", from 1990.
A Short, Sharp Shock (sometimes titled Short, Sharp Shock) is a 1990 fantasy novel by Kim Stanley Robinson. The story deals with a man who awakens without memory in a strange land and journeys through it to find the woman he woke alongside.
His journey takes him along the narrow strip of land, surrounded by ocean, which makes up the whole world. The content is unlike anything found elsewhere in Robinson's oeuvre, yet the themes remain very similar. The strong link between the human characters and the natural world connects directly to the ecological themes of his other work, especially the Mars Trilogy, but the loose and dreamlike structure is like nothing else he has written. The novel exhibits a circular structure, with the end harking back to the beginning, suggesting the theme of reincarnation that Robinson will later make the main subject of his novel The Years of Rice and Salt.
The phrase "short, sharp shock" is taken from Gilbert and Sullivan's operetta The Mikado.