Riley—an upbeat, friendly surname name—is red hot for girls and still going strong for boys. If you haven't been spending much time around babies recently, you may be surprised to learn that Riley is the most popular girls' name starting with R and also the Number 1 Irish name for girls in the US.

Audrey is one of the girls' names that have been rising due to their connection to Old Hollywood glamour — in this case the eternally chic and radiant Audrey Hepburn. Audrey has another very different appeal as one of the elite group of girl names that mean strong, brave, or powerful.

Quinn is one of the most popular Irish unisex surnames out there, a strong and attractive choice on the rise for girls but still popular for boys. A recent year saw it used for nearly 2690 girls along with 615 boys in the US, meaning its split 80:20 across the sexes.

Lydia is one of the first place names, after an area of Asia Minor whose inhabitants are credited with strong musical talent great wealth. Always among the US Top 1000 girl names, Lydia is a quietly fashionable classic.

Lila is one of the girl names with a double l sound — Lila, Lola, Layla, Leila, Lily et al — that have caught on in a major way., Delicate yet dynamic, Lila has a slightly international flair.

Mia is an appealingly unfussy multicultural name that has enjoyed a meteoric rise up the charts and is now firmly among the ten top girl names. Mia has surpassed its mother name Maria as the Number 1 girls' name starting with M.

Kit is a crisp, old-time nickname with plenty of spirit and style. In the UK it's a rising star for boys, while in the US, it is trending upwards for girls too.

Elena is at its most popular point ever in the US, thanks to its cross-cultural appeal and the overall popularity of El- names. It's more international than Ellen or Eleanor, but still accessible.

Julia was an ancient Roman imperial name given to females in the house of a Julius, as in Caesar. Its origin is shrouded in history, but possible roots include Latin iuvenis, meaning "youthful"; Greek ioulos, meaning "downy-bearded"; or Jovis, a form of Jupiter, which means "sky father".

Morgan has long been a traditional Welsh male name, a variant of the Old Welsh name Morcant, from the Welsh elements mor, meaning "sea" and cant, "circle." The female Morgan is unrelated to the male version—it is a name from Arthurian legend created for Morgan le Fay, King Arthur's half-sister and famed sorceress. Her name comes from Morgen, an Old Welsh name meaning "sea-born," and is related to the Irish name Muirgen.

Though greatly overshadowed by the trendy Olivia, Olive has a quiet, subtle appeal of its own -- and is now enjoying a remarkable comeback. Olive is one of only four girl names starting with O on the US Top 1000. Cool couple Isla Fisher and Sacha Baron Cohen chose it for their daughter, reviving the name to stylishness, and now Drew Barrymore has a little Olive too, as has country singer Jake Owen.

Strong but sweet, Leah is a classic name that doesn't feel dull or dusty. It's got plenty of dignity, grace, and pluck, making it a solid choice in the 21st century.

Piper is a bright, musical name that entered the list in 1999, one year after the debut of the TV series Charmed, which featured a Piper, and it's been a consistent riser since. Piper Kerman is the memoirist whose prison experiences provided the basis for the hit Netflix series Orange is the New Black.

While Gwen may have originated as a short form of Gwendolen and Gwendolyn, these days it frequently stands on its own. Rocker Gwen Stefani has given it a shot of cool, and parents are choosing it as a standalone more and more often—Gwen hopped back onto the US Top 1000 in 2013 after an absence of over 30 years. Gwen could also be short for Guinevere.

Combine the charming heroine of the movie Legally Blonde with supermodel Elle Macpherson and the trend toward all names beginning with "el"—Ellie, Ella, Eleanor—and you have one hit name.

First-wave Irish name and place name—the poetic name for Ireland—now supplanted by newer alternatives such as Maeve and Delaney.

Kayla is a modern invented name that emerged in the late 1950s. It may have been inspired by the similar sounding Michaela, though it could equally have come about as a combination of the then popular name popular name Kay and the familiar -la suffix.

The sassy, steel magnolia appeal of Oscar-winning Reese (born Laura Jeanne—Reese is her mother's maiden name) Witherspoon has single-handedly propelled this formerly boys’ name into girls' popularity.

Among the Top 20 names of the 1990s, today's Courtney is more apt to be the babysitter than the baby. Courtney has dropped since its peak at Number 17 in 1995. Familiar from Courtney Love and Courtney Cox.

Kimberly's heyday was in the 1960s and 70s, when it ranked among the Top 10. While it hasn't been stylish for decades, it's evidenced more staying power than some former hot girl names, remaining among the Top 300 girl names in the US, where it's stood for 70 years.