'Abdullah (bin 'Umar) (radiallaahu `anhu), used to slaughter (his sacrifice) at the Manhar. ('Ubaidullah, a sub-narrator said, "The Manhar of Allah's Apostle (sallallaahu `alayhi wasallam).")
Ibn 'Umar (radiallaahu `anhu) used to send his Hadi from Jam' (to Mina) in the last third of the night with the pilgrims amongst whom there were free men and slaves, till it was taken into the Manhar (slaughtering place) of the Prophet (sallallaahu `alayhi wasallam).
Prophet (sallallaahu `alayhi wasallam) slaughtered his sacrificial animals in Mina. That's where his 'manhar' was.