He was buried in a cemetery in Baghdad but as far as I know, the exact location of his grave is unknown.
The Tomb of Imam Ahmad Bin Hanbal is at Martyrs cemetery, near the Harb gate of Baghdad,Iraq.
Ahmad ibn Hanbal was born in 780.
Ahmad ibn Hanbal died in 855.
Christopher Melchert has written: 'Ahmad ibn Hanbal (Makers of the Muslim World)'
Khumarawaih ibn Ahmad ibn Tulun died in 896.
Ahmad ibn Muzahim ibn Khaqan died in 868.
Ahmad ibn Ajiba was born in 1747.
Ahmad ibn Ajiba died in 1809.
Ahmad ibn Tulun was born in 835.
Ahmad ibn Tulun died in 884.
Ahmad ibn Yusuf was born in 835.
Ahmad ibn Yusuf died in 912.
Ahmad ibn Ridwan died in 1607.