One of the small villages that lay in the White Mountains, in the valley of the river Snowbourn known as Harrowdale. This placed it close to Rohan's capital of Edoras, and indeed it was on the road between Edoras and the mountain refuge of Dunharrow. Thus Théoden and his armies of Rohirrim passed through Upbourn during the War of the Ring, at the beginning of the journey that would lead them east to the Battle of the Pelennor Fields.

Notes

1	The village of Upbourn was within the realm of Rohan and had a name from the language of the Rohirrim, and so the village in this form cannot have existed before the founding of Rohan. We know, however, that the valley of Harrowdale was inhabited in earlier times, and so conceivably the Men of the Mountains or the Gondorians may have had an older settlement here that predated the coming of the Rohirrim.
2	'Upbourn' is a modernisation of the original name used by the Rohirrim, equivalent to Old English Upburnan (from burn, a brook or stream). So, literally, 'Upbourn' meant 'up the stream'. 'Up' in this context describes a place relatively near a river's source, and some distance from its mouth. This was certainly the case for Upbourn: once the Snowbourn ran past the village and out of its mountain valley, the river would flow on for many miles across the plains of Rohan before it met the Entwash, far to the east.
3	The exact location of Upbourn is not shown on any map, but we know that it lay about a mile downstream from Underharrow, and that Underharrow (as its name suggests) was directly beneath Dunharrow. Upbourn must therefore have stood somewhere close to the point marked on this map (though note that the scale has been slightly exaggerated for ease of legibility, and the villages of Upbourn and Underharrow would actually have been closer together than shown here.)

Upbourn