Stone Bridges :
During those golden days of the Ahom, a host of stone bridges were constructed in and around Rangpur. Unfortunately, except a few, others got punished. Only the stone bridge over Numdung, Darika, Dijoikhana, Rangpur Na-duar have stood the test of time. How strong and well-built these stone bridges were is well exemplified by the Numdung stone bridge near Gaurisagar. That happens to be the biggest stone bridge measuring 202 ft in length, 21.5 ft in width and 5.5 ft in thickness. For free flow of water two tunnels, each of 7 ft with exist under the stone structure. Some beautiful engraving on the side walls never fail to draw attention of the workers. Built in 1703 AD during king Rudra Singha's time this Numdung stone bridge for long three centuries has with stood heavy wear and tear, more particularly since old war II. In recent times, hundreds and thousands of heavily loaded trucks caring machineries and appliances for OIL, ONGC and the like have been plying over the stone bridge every day. In fact it is an engineering marvel deserving due conservation as a historical monuments.
Realizing the strategic importance of road connectively, the Ahom rules laid due stress on road construction through the length and breadth of the whole state. In Sivasagar district a good number of important roads were built during period of Ahom rule. Bor Ali, (Gargaon, Nazira, Joysagar, Gaurisagar, Dikhowmukh), Salaguri Ali (Gargoan-Bakata-Sepon-Salaguri), Sataiali (Khelua-Kujibali-Mesagarh-Lahdoigarh), Naga Ali (Numdung-Bezgaon-Charing-Amguri-Nagahills), Dhai Ali (Sibasagar-Saragua-Dihing Mukh), Bor Boruah Ali (Sivasagar-Borboruah, Now merged with NH 37) Barpatra Ali, Gajpuria Ali, Ramani Ali, Rahdai Ali, Kharikatia Ali etc. are some important roads built in those golden days, still rendering high public utility.