| First Mac OS that used its animal codename | 42 |
| First lyricist to receive a Pulitzer Prize | 42 |
| First ltrs. | 11 |
| First ltr. | 10 |
| First Lt.'s superior | 24 |
| First Lt.'s boss | 20 |
| First loyalty, to Polonius | 26 |
| First love, perhaps | 19 |
| First love in "Abe Lincoln in Illinois" | 49 |
| First looks at Mars and Venus? | 30 |
| First look | 10 |
| First Lola in ''Damn Yankees'' | 46 |
| First livestock animal to have its genome mapped | 48 |
| First Little Pig's material | 31 |
| First little pig's building material | 40 |
| First Liston/Clay fight result, in brief | 40 |
| First lines | 11 |
| First line on many a legal document | 35 |
| First line on an IRS form? | 26 |
| First line of verse to a solver | 31 |
| First line of quote | 19 |
| First line of many puns | 23 |
| First line of “Misty” | 29 |
| First line of an ode to secretaries | 35 |
| First line of an equinoctial verse | 34 |
| First line of a Seuss classic | 29 |
| First line of a rhyme | 21 |
| First line of a nursery rhyme | 29 |
| First line of a limerick | 24 |
| First line of a couplet pertinent to this puzzle | 48 |
| First line of a "Stepquote" toast | 43 |
| First line of "Moby-Dick" | 35 |
| First lights | 12 |
| First light of day | 18 |
| First light | 11 |
| First letters | 13 |
| First letter: Abbr. | 19 |
| First letter, to Aristotle | 26 |
| First letter, to Arabic speakers | 32 |
| First letter, in signaling | 26 |
| First letter, in Hebrew | 23 |
| First letter of the Hebrew alphabet | 35 |
| First letter of the Greek alphabet | 34 |
| First letter of the Arabic alphabet | 35 |
| First letter of "zebra" when it rhymes with "Debra" | 71 |
| First letter of "census," e.g. | 40 |
| First letter in the second quarter of the Greek alphabet | 56 |
| First letter in the last third of the Greek alphabet | 52 |
| First letter in the fourth quarter of the Greek alphabet | 56 |
| First letter in Israel | 22 |
| First letter in communications | 30 |
| First letter in Bathsheba | 25 |
| First letter in "thanatos" | 36 |
| First letter given to Odysseus | 30 |
| First letter for the head of Centauri? | 38 |
| First letter | 12 |
| First lessons | 13 |
| First lesson, maybe | 19 |
| First layer of plaster | 22 |
| First layer of furniture protection | 35 |
| First law of motion subject | 27 |
| First Latina nominated for the Supreme Court | 44 |
| First Latin American Olympics host | 34 |
| First Latin American country to nationally legalize same-sex civil unions | 73 |
| First last name tag | 19 |
| First language of Hank's neighbor on "King of the Hill" | 69 |
| First landfall north of Oman | 28 |
| First lady? | 11 |
| First Lady: 1929 | 16 |
| First lady/pop star Carla | 25 |
| First Lady, often | 17 |
| First lady, no kidding | 22 |
| First lady, May 7, 1988? | 24 |
| First Lady's title | 22 |
| First lady's residence? | 27 |
| First lady's residence | 26 |
| First lady's namesakes | 26 |
| First lady's mate? | 22 |
| First lady's man? | 21 |
| First lady's man | 20 |
| First lady's hype? | 22 |
| First lady's home? | 22 |
| First lady's home | 21 |
| First lady's garden site? | 29 |
| First lady's garden | 23 |
| First Lady's first name | 27 |
| First Lady's designation | 28 |
| First lady ___ McKinley | 23 |
| First lady with bangs | 21 |
| First Lady whose maiden name was Duarte | 39 |
| First lady who wrote "Millie's Book" | 50 |
| First Lady who went to Harvard Law School | 41 |
| First lady who was once a prominent radio actress | 49 |
| First lady Truman | 17 |
| First lady played by Madonna | 28 |
| First lady on Olympus | 21 |
| First lady on Mt. Olympus | 25 |
| First lady on Mount Olympus | 27 |
| First lady of the United States (1963-1969) | 43 |
| First lady of the United States (1953-1961) | 43 |