The construction of the telegraph lines up until about 1900 is described as follows:

1. first line The Exchange to South Head-Redfern-Liverpool;
2. first line south to Victoria;
3. first line north to Queensland;
4. first line to South Australia from NSW;
5. line extensions within the five regions of New South Wales as shown in the following map.

In the Central Telegraph Office in Britannia House in the 1870s, the central room upstairs was but small - about 30ft x 15ft - and it had a large table down the centre. On the table, connected back to back, were six telegraph instruments which were the starting point of the following lines or circuits:

1. the line to Albury, which office retransmitted telegrams to and from Victoria. It was also able to do a little wayside business with intermediate offices.
2. the line to Tenterfield where telegrams were repeated for Queensland;
3. the line to West Maitland, Newcastle, Grafton, Casino, etc.
4. the line west to Bathurst and beyond;
5. a line to Wentworth - the repeating station for South Australia. This line was also able to look after a number of stations including Wagga and Deniliquin
6. a line to Goulburn, bifurcating there, one leg reaching Kiandra and the other reaching Eden.

Changes to the operations of these lines make discussion of line construction difficult. Instead descriptions are grouped within regions of the Colony. Details of the lines and the Telegraph Offices in each region can be obtained by clicking on the appropriate hyperlink.

Further complicating the discussion of line construction is that so many activities were happening at one time - in NSW and in the other Colonies. For example, in July 1859, some of the activities in NSW included:

• tenders were being reviewed for the construction of the second line from Sydney to Albury;
• the posts for the line to Bathurst had passed Penrith;
• good progress was being made from Penrith to Windsor;
• Mr. Gisborne was in the colonies to endeavour to make arrangements for carrying out telegraphic communication between Great Britain and Australia via the North Eastern coast.

In addition, the Omeo had arrived at Melbourne with the submarine cable for the Tasmania line and it was anticipated this would be laid in July or August;

Far West extends from: SA border to 144° east (just past Ivanhoe); From the Queensland border south to about 148° south. Telegraph offices in this region.	North Central extends from: The Far West region east to the first line to Queensland; Queensland border to 32° south (level with Scone and between Cobar and Mount Hope). Telegraph offices in this region.
		North East extends from: The line to Queensland and east to the coast; The Queensland border to Sydney. Telegraph offices in this region.
		Central West extends from: the Far West region (near Mount Hope) east to the first line to Queensland; the North Central region below Gilgandra south to the Riverina Murray region above Griffith but south of Cootamundra and to the Southern line to Victoria. Telegraph Offices in this region.
Riverina-Murray extends from: the south Australian Border east to the Southern line to Victoria; a variable line to the east above Wentworth and cutting between Griffith and Cootamundra down to the NSW-Victorian border. Telegraph offices in the region.	South East extends from: the Southern line east to the coast; Sydney to the Victorian border; Telegraph offices in this region.

Private telegraph lines are not included in this discussion - partly because of the extreme difficulty in accessing the information.
In the 1864 Report by the Superintendent, Martindale states:

"no additional lines to connect line stations with business establishments have been constructed (1863-1865),
the Government requiring further legal powers for the purpose. A bill to confer these powers is to be submitted to the House".