Talk:K-ON!! Original Soundtrack Vol. 2/@comment-11003905-20130618085105

夕日の綺麗なあの丘で can be split as (((夕日-の)綺麗-な)(あの-丘))で, and thus is romanized to Yuuhi no Kirei na ano Oka de. Here, na is attributive and ano is a separate word meaning 'that'.

The whole phrase is translated into "on that hill, where the sunset is beautiful". Otherwise, "on the hill [...]" would make perfect sense also. However, note that it can never be "on that beautiful hill"; adjective kirei na 'beautiful' is attached to yuuhi 'setting sun (lit. evening sun)', not oka 'hill'.