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

http://mirror.vtti.vt.edu/centos/6.10/isos/i386/
http://mirrors.advancedhosters.com/centos/6.10/isos/i386/
http://mirror.cogentco.com/pub/linux/centos/6.10/isos/i386/
http://mirror.ash.fastserv.com/centos/6.10/isos/i386/
http://mirror.vcu.edu/pub/gnu_linux/centos/6.10/isos/i386/
http://mirror.cs.vt.edu/pub/CentOS/6.10/isos/i386/
http://repo1.ash.innoscale.net/centos/6.10/isos/i386/
http://centos4.zswap.net/6.10/isos/i386/
http://us.mirror.nsec.pt/centos/6.10/isos/i386/
http://repos-va.psychz.net/centos/6.10/isos/i386/

http://centos.mirror.lstn.net/6.10/isos/i386/
http://mirrors.cat.pdx.edu/centos/6.10/isos/i386/
http://mirror.lax.genesisadaptive.com/centos/6.10/isos/i386/
http://centos-distro.cavecreek.net/centos/6.10/isos/i386/
http://centos-distro.1gservers.com/6.10/isos/i386/
http://mirror.sesp.northwestern.edu/centos/6.10/isos/i386/
http://centos.mirror.ndchost.com/6.10/isos/i386/
http://mirrors.mit.edu/centos/6.10/isos/i386/
http://mirrors.maine.edu/CentOS/6.10/isos/i386/
http://mirror.steadfastnet.com/centos/6.10/isos/i386/
http://repos.dfw.quadranet.com/centos/6.10/isos/i386/
http://mirror.dc2.hackingand.coffee/centos/6.10/isos/i386/
http://ftp.usf.edu/pub/centos/6.10/isos/i386/
http://repo.ialab.dsu.edu/centos/6.10/isos/i386/
http://reflector.westga.edu/repos/CentOS/6.10/isos/i386/
http://mirror.teklinks.com/centos/6.10/isos/i386/
http://centos.sonn.com/6.10/isos/i386/
http://ewr.edge.kernel.org/centos/6.10/isos/i386/
http://mirrors.raystedman.org/centos/6.10/isos/i386/
http://mirror.scalabledns.com/centos/6.10/isos/i386/
+ others, see the full list of mirrors: https://www.centos.org/download/mirrors/

Mirrors verified Wed Jan 22 13:35:37 2020 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