Sefydlwyd Oriel Môn ym 1991, ac ers agor mae wedi ceisio datblygu ac ehangu ei gasgliad celf gain. Ar hyn o bryd mae pedwar prif gasgliad yn yr amgueddfa a'r oriel - yn benodol gweithiau gan Charles Tunnicliffe, Kyffin Williams, y Chwiorydd Massey (lluniadau botanegol) a'r casgliad celf gain cyffredinol. Mae yna bolisi cryf tuag at gasglu gweithiau sy'n berthnasol i Fôn, ac mae hyn yn cael ei adlewyrchu yn yr ystod eang o baentiadau a gedwir yn yr amgueddfa. Mae'r rhan fwyaf o'r paentiadau wedi'u rhoi'n garedig i'r casgliad gan unigolion a sefydliadau preifat, ac ategir y rhain gyda phryniannau a wnaed gan yr Awdurdod Lleol. Defnyddir y casgliad ar gyfer rhaglen arddangosfeydd amrywiol sy'n newid yn barhaus, ac sy'n cael eu dangos yn yr Oriel Hanes ac Oriel Kyffin Williams. Oriel Môn was founded in 1991, and since opening has endeavoured to develop and expand its fine art collection. Four main collections are currently held at the museum and gallery – notably works by Charles Tunnicliffe, Kyffin Williams, the Massey Sisters (botanical drawings) and the general fine art collection. There is a strong policy towards collecting works with local relevance, and this is reflected in the wide range of paintings held in the museum. Most of the paintings have been kindly donated to the collection by private individuals and institutions, and these are supplemented with purchases made by the Local Authority. The collection is used as part of a diverse and ever-changing exhibition programme and displayed in the History Gallery and the Kyffin Williams Gallery.