早期华人集居在大伯公庙前的双溪古晋（Sungai Kuching）对岸。这条砂拉越河（Sungai Sarawak）的支流，约十尺宽，从花香街尽头，圣多玛主教屋的山坡下，流过圣王公庙和大伯公庙的前方，再由现在的“华族历史文化馆”邻近注入砂拉越河。大伯公庙前有一条木桥横跨双溪古晋，贯通两岸（见下图）。从前双溪古晋长有数棵野生龙眼树，而在马来话里，龙眼便称作“猫眼”(Mata Kuching），于是Sungai Kuching之名由此而来。
潮属老古晋们从先辈们口中得知，古晋这名字最先是叫“古井”（潮语发音KU-CHING)，久而久之便成就了“古晋”。当时古晋有三口井：一在大井巷最后第二间店屋的前边，可惜1939年前后被政府填掉；海唇街尾的旧市场（老巴刹）的那口古井也因市场迁到甘密街而被填掉；仅剩下大伯公庙背后的那口古井了。
另一说法是砂拉越河河旁有很多猫，而在旧马来文里，猫是“Kuching”。可是本地马来语称猫为“pusa”，所以“猫城”的传说有点质疑。
在历史文献中，古晋原名是“砂拉越”。Sarawak是旧马来字“serawak”的改写，意思是“锑”（Ilmu Kamus解释为“galian yang mengandungi belerang dan antimoni”，英文名是“antimony”）。1823年前。华人矿工从荷属加里曼丹进入砂拉越河上流的石隆门开采锑矿，出口到外地，serawak也因此成了地方名称。
很多历史书记载，古晋原名是Sarawak，James Brooke成了拉者后，改成Sarawak Proper。1872年8月12日，第二任拉者Charles Brooke改名为Kuching – 古晋。可是我从“THE PRIVATE LETTERS OF SIR JAMES BROOKE, K.C.B. RAIAH OF SARAWAK”书中读到James Brooke那时已称这里是Kuchin。1839年8月20日，在他写给John C. Templer的信中，提到：
“… We dropped up the river, taking a hasty survey, to the town of Kuchin, the distance is thirty-five or thirty-seven miles, water generally deep, but here and there with awkward rocks; on one of these, being ignorant of the river, we were wept by an eddy of tide, but got off without harm,… Sarawak or Kuchin is a newly established place and one likely to prove important in a commercial point of view. Antimony ore is produced in any quantity – gold, tin, rattans, beeswax and birds’ nests are likely procured front the surrounding country, and at the place itself is white clay, excellent for pipes, and which the Dutch would prize…”
书中还有几封信也有提起Kuchin这个名称。
另外一本书“THE EXPEDITION TO BORNEO OF H.M.S. DIDO FOR THE SUPPRESSION OF PIRACY WITH EXTRACT FROM THE JOURNAL OF JAMES BROOKE, ESQ. OF SARAWAK”作者Captain The Hon. Henry Keppel, R.N.引述第一任拉者James Brooke的日记中的一段：
“… 21st August 1839 – Our fleet were in readiness before daylight, and by 5 o’clock we left Kuching, and dropped down the river…”
书中也注解“Kuching”为“the former name of the town of Sarawak”。
古晋（Kuchin）这个名称在第一任拉者James Brooke来到之前已经存在，Alice Yen Ho在”OLD KUCHING”书中写到：
“… James Brooke had informally renamed his capital ‘Sarawak’ in 1842. There was no official acknowledgement on this. The town, country, and river shared the appellation until 1872 when Charles Brooke, his nephew and successor, officially reverted it to ‘Kuching’ and ended the confusion. ‘Kuching’ is known to have been derived from Sungai Kuching, a rivulet that flowed past the small Chinese Tua Pek Kong temple at the east end of the town before joining the Sarawak River. The rivulet was named after the mata kuching – cat’s eye – fruit tree (Nephelium nalarense) that flourished on the hill behind the temple, the Bukit Mata Kuching. (The fruit is identical to the longan in taste, but is, as its name implies, the size of a cat’s eye, and looks like one.)…”
我同意Alice Yen Ho的解说，所以“1872年8月12日，第二任拉者Charles Brooke恢复‘Sarawak’的原名 – Kuching。”
