Cleona is bordered to the north and east by North Lebanon Township (1.7 mi), to the south by North Cornwall Township (1.86 mi), and to the west by North Annville Township (0.37 mi) and Annville Township (0.47 mi).
There were 879 households out of which 33.6% had children under the age of 18 living with them, 61.1% were married couples living together, 8.2% had a female householder with no husband present, and 27.3% were non-families. 24.1% of all households were made up of individuals and 10.5% had someone living alone who was 65 years of age or older. The average household size was 2.44 and the average family size was 2.86.
In the borough the population was spread out with 23.9% under the age of 18, 7.0% from 18 to 24, 32.4% from 25 to 44, 21.9% from 45 to 64, and 14.8% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 96.9 males. For every 100 females age 18 and over, there were 94.0 males.
The median income for a household in the borough was $44,761, and the median income for a family was $52,328. Males had a median income of $34,574 versus $23,944 for females. The per capita income for the borough was $21,090. About 2.8% of families and 3.4% of the population were below the poverty line, including 1.6% of those under age 18 and 1.6% of those age 65 or over.