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.

Elise is one of those golden names that stylish but not TOO popular. Its appeal is due in large part to its French flair and to the love for El-names in general.

Ellie first took off in the UK—yes, in this nickname form—and this warm and friendly name has also become hugely popular here. In 2011, Ellie entered the US Top 100 girl names for the first time and has remained near the top of the charts ever since.

Newly fashioned but familiar and with an on-trend, unisex feel, Addison seems like the perfect solution for anyone who can't decide between Madison, Adeline, and Alison.

Popular pop name, inspired by Australian singer Kylie Minogue. It was at its height in Australia in the 1970s and early 80s; often cited as a Noongar name meaning "boomerang".

A strong, straightforward Irish unisex surname, with a merry glint in its eye, Reagan has been leaping up the popularity lists, to become one of the top girl names starting with R. Some will inevitably link it to President Ronald, but spell it Regan and it's a Shakespearean name: a daughter of King Lear.

A unique combination of a surname feel and dainty femininity, Lacey is a favorite in the UK where it ranks in the Top 500. Likely derived from the name of a place in Normandy, it might occasionally be considered a diminutive to Wallace ("Welshman") or Larissa ("citadel").