Pen yr Allt Uchaf

{{Short description|Mountain (620m) in Gwynedd, Wales}}

{{Use dmy dates|date=April 2022}}

{{Infobox mountain

| name = Pen yr Allt Uchaf

| photo = Allpenmawr.JPG

| photo_caption = Aran Fawddwy from Pen yr Allt Uchaf

| elevation_m = 620

| elevation_ref =

| prominence_m = 49

| parent_peak = Aran Fawddwy

| listing = Hewitt, Nuttall

| translation = top of the highest slope

| language = Welsh

| location = Gwynedd, Wales

| range = Snowdonia

| grid_ref_UK = SH 86644 19322

| topo = OS Landranger 124

}}

Pen yr Allt Uchaf is a subsidiary summit of Aran Fawddwy in the south of the Snowdonia National Park in Gwynedd, Wales. The summit is the highest point on a ridge branching off to the west of Aran Fawddwy's south ridge.

The summit is marked by a small cairn, and offers bird-eyes views of Cwm Cywarch. Close views of the steep south faces of Glasgwm, Gwaun y Llwyni and Aran Fawddwy are observed.{{cite book |last=Nuttall |first=John & Anne |date=1999 |title=The Mountains of England & Wales - Volume 1: Wales |edition=2nd |location=Milnthorpe |publisher=Cicerone |isbn=1-85284-304-7}}