Keep Your Chin Up
Meaning
Remain cheerful in a difficult situation.
Origin
This sounds like one of those rousing maxims that were drilled into the young of Victorian England like keeping a stiff upper lip. Perhaps surprisingly, the phrase is American. The first use of it that I can find is from the Pennsylvania newspaper The Evening Democrat, October 1900, under the heading Epigrams Upon the Health-giving Qualities of Mirth:
“Keep your chin up. Don’t take your troubles to bed with you hang them on a chair with your trousers or drop them in a glass of water with your teeth.” –
[they were easily amused in Pennsylvania in 1900].