In order to conserve the limited bandwidth available, ISO images are not downloadable from mirror.centos.org

http://mirrors.advancedhosters.com/centos/7.9.2009/isos/x86_64/
http://mirror.ash.fastserv.com/centos/7.9.2009/isos/x86_64/
http://mirror.cs.vt.edu/pub/CentOS/7.9.2009/isos/x86_64/
http://mirror.vtti.vt.edu/centos/7.9.2009/isos/x86_64/
http://mirror.centos.iad1.serverforge.org/7.9.2009/isos/x86_64/
http://us.mirror.nsec.pt/centos/7.9.2009/isos/x86_64/
http://mirror.cogentco.com/pub/linux/centos/7.9.2009/isos/x86_64/
http://mirror.vcu.edu/pub/gnu_linux/centos/7.9.2009/isos/x86_64/

http://mirror.mi.incx.net/centos/7.9.2009/isos/x86_64/
http://mirrors.greenmountainaccess.net/centos/7.9.2009/isos/x86_64/
http://mirror.nodesdirect.com/centos/7.9.2009/isos/x86_64/
http://centos.s.uw.edu/centos/7.9.2009/isos/x86_64/
http://nyc.mirrors.clouvider.net/CentOS/7.9.2009/isos/x86_64/
http://centos-distro.cavecreek.net/centos/7.9.2009/isos/x86_64/
http://mirror.facebook.net/centos/7.9.2009/isos/x86_64/
http://mirrors.raystedman.org/centos/7.9.2009/isos/x86_64/
http://repos.hou.layerhost.com/centos/7.9.2009/isos/x86_64/
http://mirror.nodespace.net/centos/7.9.2009/isos/x86_64/
http://mirror.metrocast.net/centos/7.9.2009/isos/x86_64/
http://mirror.mojohost.com/centos/7.9.2009/isos/x86_64/
http://mirrors.wcupa.edu/centos/7.9.2009/isos/x86_64/
http://mirror.steadfastnet.com/centos/7.9.2009/isos/x86_64/
http://mirrors.rcs.alaska.edu/centos/7.9.2009/isos/x86_64/
http://mirror.fileplanet.com/centos/7.9.2009/isos/x86_64/
http://mirrors.xmission.com/centos/7.9.2009/isos/x86_64/
http://mirror.dal.nexril.net/centos/7.9.2009/isos/x86_64/
http://repos.eggycrew.com/centos/7.9.2009/isos/x86_64/
http://mirror.us-midwest-1.nexcess.net/CentOS/7.9.2009/isos/x86_64/
http://or-mirror.iwebfusion.net/centos/7.9.2009/isos/x86_64/
http://distro.ibiblio.org/centos/7.9.2009/isos/x86_64/
+ others, see the full list of mirrors: https://www.centos.org/download/mirrors/

Mirrors verified Sat Dec 4 22:34:20 2021 UTC

You can also download the ISO images using bittorrent, a peer-to-peer file sharing protocol. The .torrent files can be found from CentOS mirrors. Various bittorrent clients are available, including (in no particular order of preference): utorrent, vuze (Azureus), BitTorrent, Deluge, ctorrent, ktorrent, rtorrent and transmission. Packaged copies of various torrent clients for CentOS can be found in the repositories listed in the following wiki article: https://wiki.centos.org/AdditionalResources/Repositories