Across the river, almost directly opposite Williamsport, there lies a small township, known as Armstrong. It does not now possess the same importance that it once enjoyed, because two very enterprising boroughs have been created within its original limits, namely, South Williamsport and DuBoistown. The township is bounded on the north by the two boroughs mentioned and the river; on the east by Clinton Township; on the south by Washington Township and on the west by Bastress, Susquehanna and Limestone townships. Its southern line extends along the topmost ridge of the Bald Eagle Mountain from a point below Sylvan Dell until it dips into White Deer Valley almost opposite the headwaters of Mosquito Creek. It includes within its limits both slopes of the mountain and the interesting valleys, from Loyalsock Gap to Mosquito Gap.

Armstrong was originally a part of Clinton Township and was taken from the latter in 1842 and given the name of Armstrong in honor of James Armstrong, a prominent member of the Lycoming County bar, and afterwards a justice of the supreme court of Pennsylvania. Three-fourths of its present surface is very hilly and mountainous, as the Bald Eagle range erosses through it almost directly east and west. It is the eighteenth in size in the county and contains 13,440 acres.

At one time Armstrong Township included within its limits all the territory lying along the south side of the river from Loyalsock Gap to Mosquito Creek, upon which the boroughs of South Williamsport and DuBoistown are now built, and which was known as the "Lower Bottom" as contradistinguished from the "Upper Bottom" of the river which extended from the base of the mountain above the mouth of Mosquito Creek to a point nearly opposite Jersey Shore.

Perhaps the most important part of Armstrong Township, as it now exists, is that known as Mosquito Valley. This section possesses great historic interest by reason of the fact that through here and down the stream led the main Indian trail from Fort Augusta to New York and Canada. This was the famous Culbertson Trail.

One of the earliest settlers in Mosquito Valley was Marcus Huling, who came there about the year 1795. A number of land warrants had been located in the valley prior to that time by various persons, but no actual settlements were made on them. These tracts were subsequently purchased by Colonel Thomas Hartley, who had commanded several expeditions against the Indians in this section and who probably knew the great fertility of the soil in the valley. Four of these tracts, known respectively as "Kelsoe," "Ledbury," "Grammont" and "Hartley," were purchased by Thomas and Seely Huling, sons of Marcus Huling, and turned over to their father.

Marcus Huling was a very enterprising man and soon made his influence felt in the valley. He built a saw mill, a grist mill and a distillery. He cleared up a fine tract of land and made of it a wonderfully productive farm. People came from the other side of the mountain to bring their grists to be ground, carrying them on their backs, or on horseback, following the old Indian trail. This trail subsequently became the main wagon road leading up the valley and over the mountain. The lumber sawed at the Huling mill was hauled down the creek to the river, where it was made into rafts and floated to market. There are a number of Marcus Huling’s descendants still living in the county. Mosquito Valley is now principally used for the storage reservoirs of the Williamsport Water Company.

Hagerman’s run, which empties into the river just below Williamsport Market Street bridge, and which is also used by the Williamsport Water Company for its lower storage reservoirs, has its rise in Armstrong Township at the base of the mountain and flows down through the second gap in the mountain within the limits of this township. It was named for Aaron Hagerman, who was born in Holland and came to America at an early day. He came to Armstrong Township shortly after the Revolutionary war and made a settlement near the present site of Koch’s brewery. He soon moved away, however, but the stream on whose banks he lived still bears his name. At its mouth was a famous place during the lumber days of the past for rafts to tie up for the night, on their way down the river. The original name of the town at the south end of the Market Street bridge was Rocktown, given to it at the time because of the rocky character of the ground.

At the lower end of Armstrong Township along the river is another short stretch of wonderfully fertile land extending from the Pennsylvania railroad bridge to Sylvan Dell. The lower farm was originally owned by John Gibson, one of the best known and well beloved men in this section of Pennsylvania, and one of the most enterprising of his day. He was not only a successful farmer, but a progressive man in all lines of material development. He was one of the first directors of the Loyalsock Turnpike Company and also an active spirit in the building of the first bridge over the Susquehanna River in Lycoming County on the site of the present Market street bridge.

One of the earliest improvements in Lycoming county at an early day was the Loyalsock turnpike, which crosses the mountain through Loyalsock gap and has its beginning in Armstrong Township. Until only a few years ago it was a toll road with a gate at the top of the mountain. It was built originally as a short cut from Williamsport to Northumberland and was followed by the old stage coaches. It is interesting to consider, in this age of lightning express trains, automobiles, motorcycles and flying machines, what a trip to Northumberland, only forty miles distant, meant in the days of the stage coach. The first line from Williamsport was started August 25, 1809. Its schedule and rates were as follows:
Leave Williamsport Friday morning at 4 o’clock A. M., arrive at Northumberland at 6 o’clock P. M. Start from Northumberland at 5 o’clock A. M. and arrive at Williamsport at 7 o'clock P. M. Fare, one way $2.25. Way passengers six cents per mile. Fourteen pounds of baggage free.

There is another important place within the limits of Armstrong Township, as it is at present constituted, and that is Sylvan Dell, the well known summer resort. It is located at the base of the mountain, near the river on the south side, and has become quite famous as a breathing place during the hot summer months. A number of Williamsport people own cottages at Sylvan Dell, where they spend a part of the heated period, and it is also reached by steamboats from Williamsport during the season.

The balance of Armstrong Township is almost entirely mountain land and yet one is surprised in traversing it to see how productive some of these mountain farms have become under the careful management of the sturdy Germans that own them. Some one has said that Andrew Carnegie would have grown rich if he were placed on a desert island with no company but himself, and this is measurably true. But it is just as certain that some of the rugged German farmers, such as dwell in the mountainous parts of Armstrong Township, could raise crops on an asphalt pavement.