Likely a variant of Dallan or Dale-derived names, associated with a valley or small dale.
Dallen is a name with multiple plausible origins that have woven together over time. It may derive from the Welsh personal name Dafydd (the Welsh form of David, meaning 'beloved'), filtered through anglicization into forms like Dallin and Dallen. It also connects to Dallin as a Scandinavian surname and place-name element — dal meaning 'valley' in Old Norse — giving it a second etymological strand of quiet, geographical dignity.
Some American bearers trace it to Irish roots, where similar sounds appear in Gaelic place-names and surnames. Dallin Oaks, a prominent figure in The Church of Jesus Christ of Latter-day Saints who became First Counselor in the First Presidency, gave the name Dallin particular resonance within LDS communities, where it has been a familiar given name for several generations. The variant spelling Dallen reflects the American fondness for phonetic individuality within traditional-sounding names — a name that fits comfortably beside other nature-adjacent, Anglophone choices without being indistinguishable from them.
In the broader landscape of American naming, Dallen occupies an interesting position: it sounds established without being common, regional without being provincial. It shares the warmth of names like Dalton, Daylon, and Declan while maintaining its own distinct identity. Parents who choose Dallen often appreciate that it is pronounceable on first encounter, carries no distracting pop-culture associations, and yet remains rare enough that a Dallen in any classroom is likely to be the only one — a combination that is harder to achieve than it sounds.