If you don't want to setup your own local Ubuntu mirror,then you may find that updating your sources list to automatically find and fetch from the closest mirror drastically increases the speed of your updates. All you have to do is add the following lines to the top of your etc/apt/sources.list file:
16.04 Xenial Users
deb mirror://mirrors.ubuntu.com/mirrors.txt xenial main restricted universe multiverse deb mirror://mirrors.ubuntu.com/mirrors.txt xenial-updates main restricted universe multiverse deb mirror://mirrors.ubuntu.com/mirrors.txt xenial-backports main restricted universe multiverse deb mirror://mirrors.ubuntu.com/mirrors.txt xenial-security main restricted universe multiverse
14.04 Trusty Tahr Users
deb mirror://mirrors.ubuntu.com/mirrors.txt trusty main restricted universe multiverse deb mirror://mirrors.ubuntu.com/mirrors.txt trusty-updates main restricted universe multiverse deb mirror://mirrors.ubuntu.com/mirrors.txt trusty-backports main restricted universe multiverse deb mirror://mirrors.ubuntu.com/mirrors.txt trusty-security main restricted universe multiverse
12.04 Precise Users
deb mirror://mirrors.ubuntu.com/mirrors.txt precise main restricted universe multiverse deb mirror://mirrors.ubuntu.com/mirrors.txt precise-updates main restricted universe multiverse deb mirror://mirrors.ubuntu.com/mirrors.txt precise-backports main restricted universe multiverse deb mirror://mirrors.ubuntu.com/mirrors.txt precise-security main restricted universe multiverse
