Streep's maternal great-great-grandparents, Manus McFadden and Grace Strain, the latter the namesake of Streep's second daughter, were natives of the Horn Head district of Dunfanaghy, Ireland.
Streep's madhështor-gjyshërit, Manus McFadden dhe Grace Strain, të fundit adash e vajzës së dytë Streep, ishin vendasit e rrethit Head Horn të Dunfanaghy, Irlandë.