Refferendwm dros sefydlu Cynulliad Cenedlaethol
Refferendwm 18 Medi 1997 ar sefydlu'r Cynulliad Cenedlaethol, sef Senedd Cymru erbyn hyn.

 Yr wyf yn cytuno y dylid cael Cynulliad Cymreig / I agree that there should be a Welsh Assembly
neu/or
 Nid wyf yn cytuno y dylid cael Cynulliad Cymreig. I do not agree that there should be a Welsh Assembly.

Canlyniadau 

Awdurdod Lleol
Etholaeth
% bleidleisiodd
Cytuno
%
Anghytuno
%
Difethwyd
Abertawe
174,725
47.1
42,789
52.0
39,561
48.0
351
Blaenau Gwent
55,089
49.3
15,237
56.1
11,928
43.9
147
Bro Morgannwg
89,111
54.3
17,776
36.7
30,613
63.3
149
Castell-nedd a Phort Talbot
106,333
51.9
36,730
66.5
18,463
33.5
246
Caerdydd
228,571
46.9
47,527
44.4
59,589
55.6
407
Caerffili
129,060
49.3
34,830
54.7
28,841
45.3
256
Casnewydd
94,094
45.9
16,172
37.4
27,017
62.6
146
Ceredigion
54,440
56.8
18,304
59.2
12,614
40.8
185
Conwy
87,231
51.5
18,369
40.9
26,521
59.1
130
Gwynedd
92,520
59.8
35,425
64.1
19,859
35.9
183
Merthyr Tudful
44,107
49.5
12,707
58.2
9,121
41.8
122
Pen-y-bont ar Ogwr
100,400
50.6
27,632
54.4
23,172
45.6
249
Powys
96,107
56.2
23,038
42.7
30,966
57.3
265
Rhondda Cynon Tâf
175,639
49.9
51,201
58.5
36,362
41.5
137
Sir Ddinbych
70,410
49.7
14,271
40.8
20,732
59.2
99
Sir Fynwy
65,309
50.5
10,592
32.1
22,403
67.9
116
Sir y Fflint
113,181
41.0
17,746
38.2
28,707
61.8
118
Sir Gaerfyrddin
133,467
56.4
49,115
65.3
26,119
34.7
289
Sir Benfro
88,720
52.6
19,979
42.8
26,712
57.2
156
Torfaen
69,505
45.5
15,756
49.8
15,854
50.2
90
Wrecsam
96,787
42.4
18,574
45.3
22,449
54.7
76
Ynys Môn
54,044
56.9
15,649
50.9
15,095
49.1
86
Cyfanswm:
2,218,850
 50.1 
559,419
50.3
552,698
49.7
4,003
Data etholiadau