Below is a very interesting piece that helps to answer the question 'What are the oldest towns in South Africa?'. It appeared in the book Town Planning in South Africa written by T.B. Floyd in 1960. The piece does not mention pre-colonial African settlements so feel free to add these in the comments section below the article.
The first settlement [what would become Cape Town] comprised a fort in which all the settlers lived and large gardens near the fort in which fresh produce was grown. A little town began to spring up near the fort when buildings were erected by the free burghers [individuals permitted to establish themselves as farmers and tradesmen].
With the expansion of the Colony it became necessary to decentralise administration and in 1679 Governor Simon van der Stel established a further settlement and town which was named Stellenbosch. Here a Landdrost was appointed and a drostdy established. This resulted in a local court and a form of local government being set up for the new district.
The change from cultivation to stockfarming by a section of the population resulted in rapid expansion of the colony and further decentralisation. After Stellenbosch, Swellendam was established in October 1746 and later, in 1786, Graaff Reinet was laid out.
Old Map of Graaff Reinet hanging in the Drostdy Hotel (Photographed by The Heritage Portal)
Four settlements had by this date been established but only Cape Town was really a town. The other three were very small places being merely government administrative centres with a few houses. In 1807 Stellenbosch consisted of only 93 houses, Swellendam 18 and Graaff Reinet 20. In each centre there was a church and the district formed the area of the congregation.
Business centres did not exist in the district of Cape Town where there was a concentration of population. The needs of the farmers in the other three districts were served by travelling pedlars, who moved from farm to farm.
In addition to the four administrative towns, the town of Simonstown was established in 1680 as a harbour and naval station.
The next period of town establishment was commenced when the vacant spaces of land left by the earlier expansion of white settlement were filled up. This meant an increase in population and consequently the need for additional administrative and church centres. New districts and congregations were created by subdividing the old ones.
Tulbagh was the first town to be created under this process, and was established in 1795. It was followed by George in 1800 and Uitenhage in 1804 and then many others.
The second period of town establishment may be taken from 1790-1825. Towns established during this period, with the exception of a few, were intended to serve as administrative centres for new districts or subdistricts. The few exceptions were towns established on the eastern border for the purposes of defence, and those established for such purposes as a mission station, church centre, harbour or settlement.
Examples of military towns are Grahamstown, Cradock and Fort Beaufort. Port Elizabeth started as a small trading and port centre in 1812. Griquatown began as a mission station in 1812, Bathurst was laid out as a 'settlers' town and Caledon was established as a church town.
Old Fort Port Elizabeth (The Heritage Portal)
In the first and second periods of town establishment the initiative came from the Government except in a few cases. A characteristic of the third period was the initiative taken by the Dutch Reformed Church, particularly in the Cape Province or Cape Colony as it was then known. The third period may be considered as dating from 1826 to 1900 and during this time a great number of towns were established.
The procedure in establishing a new town usually followed similar lines and a description hereunder of that adopted in the case of a typical government sponsored town and of one initiated by the church will be of interest.
When it was decided to form a new district in the time of Governor Janssens, Captain Alberti was instructed to select a site for the new town. Together with a committee of prominent farmers a site on the Zwartkops River was selected. The developments on the farm were purchased as the whole farm was to be the town area and a town was laid out in 1804. The new town and district were called Uitenhage and Captain Alberti became the first Landdrost of this town and district. This may be cited as a typically government sponsored town.
Robertson may be regarded a typical example of a church town.
In 1852 a resolution was taken by the Church Council of the Dutch Reformed Church of Swellendam to establish a new congregation. Dr Robertson was minister of the Swellendam congregation, which had expanded to such an extent that he could not cope with the work involved.
A site for a new town was investigated by a committee appointed for the purpose and the choice fell on the farm 'Het Roode Goud aan de Hoopsrivier', which in English means 'The Red Gold on the River of Hope'. A decision was then taken to purchase the farm and the Governor's permission was sought to establish and layout a new town.
After obtaining the necessary permission H. van Reenen, a land surveyor, was instructed to design and peg out the streets and erven of the town and he functioned as a town planner would today. The first sale in Robertson took place on 11th April 1854.
In Natal the first settlement was that of a few traders at Durban, where a small hamlet grew up in 1835. There was no government at the time in Natal but four or five years later the streets of the new town were laid out by Cato on instruction from the Voortrekker Government.
Old Court House Durban - One of the oldest buildings in the City (The Heritage Portal)
Natal south of the Tugela River became the Republic of Natalia and Pietermaritzburg was laid out in 1839 by the Voortrekkers to serve as administrative capital of the Republic.
The first town established in the Orange Free State was that of Winburg. Hendrik Potgieter, the Voortrekker leader selected the site of Winburg and later that of Potchefstroom. Winburg was the seat of the Adjunct Volksraad and was thus a sub-capital of the Republic of Natalia. Many other towns were established as administrative and church centres after this date. In fact most of the Orange Free State town came into existence before 1900.
In the Transvaal the first town to be established by the Voortrekkers was that of Potchefstroom in 1838. The first settlement of white persons as an organsied community was that of the Voortrekker group under Hendrik Potgieter who settled on the Mooi River in 1838. It served as a sub-capital for the Transvaal portion of the Republic of Natalia and was the seat of the Adjunct Volksraad in the same way as Winburg was for the Free State. Later it became the Capital of the Transvaal Republic for a short period. Potgieter later moved to Ohrigstad and set up the Volksraad for Transvaal at this centre in 1845. A settlement took place at Klerksdorp in 1837, from which a small town arose. Lydenburg was established in 1849, and became the capital of the Transvaal in place of Ohrigstad where malaria had taken a heavy toll on the inhabitants.
Pretoria was established largely by the initiative of M.W. Pretorius in 1855 and was selected as the new capital of the Transvaal by him in 1860. The town was named after his father Andries Pretorius, Commandant General of the Republic of Natalia.
Most of the old Transvaal towns were established for administrative purposes and to serve their districts as social and commercial centres. The Government established a town in every district. From 1886 onwards many of the mining towns were laid out. These were laid out by the Government under the Gold Law of 1871 and were regarded at the time as temporary camping towns only. The land was subdivided into 'standplaatsen' or stands which were leasehold and not freehold erven as in the case of other towns.