Busia is a border town in Uganda and Kenya. Legally, there is a Busia, Uganda, and an adjacent Busia, Kenya.
Busia is not usually of much interest to travelers, but it's a great place to take a look at, an impressive border with fine buildings and security checkpoints.
There are minibuses, taxis and buses coming from Kampala, which takes four hours, and from Jinja, two hours. From the Kenya side of the border there are minibus taxis and buses from Kisumu, two hours and Nairobi, 8 hr. Minibus taxis also come from Malaba, one hour. Other means of transportation are bodaboda (being carried on a bicycle as the cycler takes you from one destination to another), extremely cheap, as little as Ksh 20.
A large number of coach companies serve Busia on the way to Nairobi, Kampala, and other destinations. Examples include Modern Coast (which can be reserved online), Easy Coach, and many others. If you book a seat on an international service, you can simply proceed to immigration and meet your coach there.
On the Uganda side, the "main stage" (matatu terminal) is about 3 km from the border. You can cover the distance with a motorcycle taxi for USh 2000.
The border crossing has been rebuilt and streamlined. Exit and entry formalities can be conducted at adjacent booths in the same building. Other services are also available.
Travelers needing to acquire a visa will need to have cash in the appropriate currency. The money changers that mob the immigration area have a terrible reputation and it is best to avoid them.
The process is not that secure and it is possible to accidentally cross the border illegally. Make sure your passport contains all the right entry and exit stamps or you may encounter trouble down the line.
Visa fees when entering Uganda may be paid in US dollars only. The border agents generally have change, but packing exact change is still recommended, if only due to the chance of getting back a counterfeit.
After passing immigration, there is an ATM and some currency exchange booths. Besides exchanging between Ugandan shillings and major international currencies, you can also exchange Ugandan and Kenyan shillings or Kenyan shillings to US dollars. As of April 2018, the rates were very favorable and much better, as good as 1% from Interbank.
2nd-order administrative division
Primary administrative division