The Passumpsic River passes southerly through town and its waterpower was once used for eight sawmills, two tanneries, a carriage factory, and a starch factory. Miller's Run and Branch Brook feed into the River. There are three small ponds in Lyndon: the smallest is Stuart Pond, just west of Route 5 in the southern part of town; Bean Pond is on the town line with Wheelock; Nichols Pond is on the southern boundary and lies partly in St. Johnsbury. All the ponds are named for local residents.
North of the Lyndon Center cemetery there are rolling sand dunes, forming a miniature desert which is unique in Vermont. Reforestation is being done to combat soil erosion.
In 1959, the Wilder (W. Arthur Simpson) Farm and, in 1985, the Esterbrook Farm, were given the Century Farm Award. The award acknowledges 100 years or more of ownership in the same family.
Lyndon's oldest dairy farm ceased operation in September 1990. Ila Ruggles sold her herd because good farm help was impossible to find. Her husband's great-great-grandfather, William F. Ruggles, had purchased 100 acres of land on Pudding Hill in 1794 for 100 silver dollars.
On November 27, 1894, a fire started in the back room of Webb's hotel at Elm and Depot Streets. There were a total of 23 buildings lost on both sides of Depot Street from Main to the Railroad Station.
On May 24, 1897, a fire started in the Lyndon House in Lyndon Corner. All of the west side of Main Street, south from York Street, was destroyed.
On January 21, 1924, a fire started in Stern's Store, destroying every building on the south side of Depot Street from Elm to Broad. One hundred fifty people were left homeless.
Other fires in single buildings: November 28, 1867 the Walker's Hotel; January 2, 1922 Thompson Hall at Lyndon Institute; August 27, 1967 the First Congregational Church; and the Fletcher (Ide) Block destroyed in 1924 after less serious fires in 1888, 1899, 1910 and 1913.
In 1869 the Passumpsic River rose 14 feet above normal levels destroying 27 public, 10 private, and 2 railroad bridges. Virtually every road in town had been damaged.
In November of 1927, the River rose 18 feet above normal levels carrying away 16 bridges. Eight other bridges, as well as businesses and residences were damaged.
1973 had two floods, June 30-July 1 and again in December.
The Hurricane of 1938 caused damage to the town.
The years 1888 and 1925 had notable blizzards.
In July of 1895 hordes of grasshoppers destroyed crops in the Egypt section of town.