How many direct descendants of Crinan The Thane are there from an unbroken line?

two patrilineal lines:

Crínán of Dunkeld is your 27th great grandfather.
You  → Henry Marvin Welborn (your father) → Henry Marvin Welborn, Sr. (his father) → Francis "Fannie" Pernerviane Welborn (Davis) (his mother) → Primma M. Pridgen (her mother) → Sarah Autra Pridgen (Pitchlynn) (her mother) → Major John Pitchlynn, Sr. (her father) → Jemima Sally Pitchlynn (Hickman) (his mother) → Marie Hickman (Hornbeck) (her mother) → Janneke aka Jane Hornbeck (Kortright) (her mother) → Sarah Kortright (Ten Eyck) (her mother) → Jannetje Aldertse Roosa (her mother) → Captain Aeldert Hymansz Roosa (her father) → Heijmen Guijsbert Roosa (his father) → Gijsbert Goertzen Roosa (his father) → Jutta van Heukelom, gezegd van Rosendael (his mother) → Otto Ottensz van Heukelom (her father) → Otto van Heukelom (his father) → Otto Ottensz van Heukelom (his father) → Aleid d'Avesnes (his mother) → Guido (Gwijde Gui) d'Avesnes, bishop of Utrecht (her father) → Aleid van Holland (his mother) → Floris IV, count of Holland (her father) → William I, Count of Holland (his father) → Ada de Huntingdon (of Scotland), Countess of Holland (his mother) → Henry, 3rd Earl of Huntingdon (her father) → David I, King of Scots (his father) → Malcolm III, 'Canmore', King of Scots (his father) → Duncan I, King of Scots (his father) → Crínán of Dunkeld (his father)

Maldred mac Crínán, Earl of Dunbar is your 26th great grandfather.
You → Henry Marvin Welborn (your father) → Henry Marvin Welborn, Sr. (his father) → Calhoun H. Welborn (his father) → Sarah Elizabeth Welborn (Dykes) (his mother) → Benjamin Franklin Dykes (her father) → William George Dykes (2 Dykes-Revolutionary War Loyalist), Sr. (his father) → George Edward Dykes, Sr. (his father) → Edward George Dykes (his father) → Edward Deakes (Dyeck) (his father) → Thomas Dyeck (his father) → Edward Dykes (his father) → Jane Dykes (Lancaster), of Sockbridge (his mother) → Sir Lancelot Lancaster, MP (her father) → Elizabeth Lancaster (Lowther) (his mother) → Mabel Lowther (Lancaster) (her mother) → Margaret Lancaster (Strickland) (her mother) → Thomas de Strickland, MP (her father) → Margaret Lathom (his mother) → Sir Thomas de Lathom, I (her father) → Sir Robert de Lathom, Knight (his father) → Joan de Millom (his mother) → Juliana de Boyville (de Ireby) (her mother) → Adam de Ireby (her father) → Orm de Ireby (his father) → Gospatrick of High Ireby, Lord of Workington (his father) → Gunhilda, of Northumbria (his mother) → Gospatric, Earl of Dunbar (her father) → Maldred mac Crínán, Earl of Dunbar (his father)

I might most for sure descend from of course many royal lines I have but Crinan is on a unproven bloodline I'm still validating so not yet for me cuzzo.

Ya and I are cousins through the Keene family not the Washingtons so I don't share the Washington descent from Crinan.

Crínán of Dunkeld

I have many lines from Crinan, but as I'm 1-finger typing on my phone, I'll only post the Washington line as i assume you are most interested in that.

A couple of points, though...
Henry of Huntingdon was the 2nd GGS of Crinan. His daughter, Marjorie, m. 3 times. I directly descend from her & each husband:
Conan IV de Penthievre, Duke of Brittany - 25th GGF
Humphrey IV de Bohun, Constable of Eng - 23rd GFF
William Fitz Patric de Washington - 28th GGF

Marjorie 's brother, David, is my 22nd GGF
Her sister, Ada, is my 25th GGM
Her brother, William "the Lion" is my 24th GGF

WASHINGTON Line:

Crinan of Dunkeld -->
Maldred mac Crinan -->
Maldred Fitz Maldred -->
Uchtred Fitz Maldred -->
Dolfin Fitz Uchtred -->
Sir Patric fitz Dolfin -->
William Fitz Patric de Washington -->
M. Marjorie de Huntingdon
William de Washington II -->
William de Washington III -->
Sir Walter de Washington -->
William de Washington -->
Sir William de Washington --<
Eleanor Washington -->
Dionysia Tempest -->
Sir John Mallory -->
Sir William Mallory -->
Sir John Mallory -->
Sir William Mallory -->
Elizabeth Stapleton -->
Sir Robert Stapleton -->
Jane Wyvill -->
Sir Marmaduke Wyville -->
Mary Beckwith -->
Marmaduke Beckwith -->
Grace Lucas -->
Elizabeth Briggs -->
Priscilla Barker (my 7th GGM)

I'm directly descended on both sides of my tree.

Looks like I have multiple (more than two) direct lines of descent from Crínán of Dunkeld

Macbeth, King of Scots is my 1st cousin x28 on my father's side of the tree.

Jan Sem Dambæk → Hanna Frederikke Sem (your mother) → Ingrid Mürer (her mother) → Hanna Fredrikke Moe (her mother) → Hanna Frederikke Sejersted (her mother) → Johannes Mathias Sejersted (her father) → Oberst Fredrik Christian von Sejersted (his father) → Dorthea Katrine Klingenberg (his mother) → Sara Johanne Hansdatter Arentz (her mother) → Hans Christian Petersen Arentz (her father) → Peter Henrichsen Arentz (his father) → Heinrich Arentz (his father) → Heinrich III von Sachsen-Lauenburg, Erzbischof v. Hamburg-Bremen, Bischof v. Osnabrück u. Paderborn (his father) → Franz I von Sachsen-Lauenburg (his father) → Herzog Magnus I von Sachsen-Lauenburg (his father) → Herzog Johan V von Sachsen-Lauenberg (his father) → Adelheid von Pommern (his mother) → Bogislaw IX, Duke of Pomerania (her father) → Bogislaw VIII of Pomerania in Hinterpommern (his father) → Adelheid von Braunschweig (his mother) → Ernst von Braunschweig, Duke of Brunswick-Grubenhagen (her father) → Agnes, Duchess of Brunswick-Grubenhagen (his mother) → Margherita di Sicilia (her mother) → Isabella of England, Holy Roman Empress, Queen consort of Sicily (her mother) → John I "Lackland", King of England (her father) → Henry II "Curtmantle", King of England (his father) → Empress Matilda (his mother) → Matilda of Scotland (her mother) → Malcolm III, 'Canmore', King of Scots (her father) → Duncan I, King of Scots (his father) → Crínán of Dunked

I am overwhelmed by the amount of responses thus far, and am extremely greatful for everyones input.

This means alot to me because everyone who posts here, is family and it is amazing to see just how many people, come from just this one great man. ~

Crínán of Dunkeld is your 26th great grandfather.
Du → Alma Zawidzka Michalska (your mother) → Mieczyslaw Zawidzki (her father) → Michail Piotrowicz Daragan (his father) → Peter Мikhailovich Daragan (his father) → Eva Jakobsdotter Fock (his mother) → Col. Jakob Johan Magnusson Fock, till Humala (her father) → Magnus Johann (Maksim) von Fock, a.Sastama (his father) → Hans Fock, till Patz a. Raustfer (his father) → Helena Margareta Pröbsting (his mother) → Martin Martinsson von Pröbsting (her father) → Marthen Harmensson Pröbsting (his father) → Helene Bertholdsdotter von Plettenberg (his mother) → Berthold von Plettenberg (her father) → Ritter Diderich von Plettenberg, Herr zu Nehlen (his father) → Mechteld von Plettenberg (his mother) → Mechthild von Schorlemer (her mother) → Count Werner von Asseburg (her father) → Agnes von Büren (his mother) → Ermgard von Broich (her mother) → Agnes van Altena (her mother) → Friedrich II, Graf von Altena und Isenberg und Limburg (her father) → Mechthilde von Holland zu Styrum (his mother) → Ada de Huntingdon, Countess of Holland (her mother) → Henry, 3rd Earl of Huntingdon (her father) → David I, King of Scots (his father) → Malcolm III, 'Canmore', King of Scots (his father) → Duncan I, King of Scots (his father) → Crínán of Dunkeld (his father)

A minor correction: Macbeth is my 1st cousin x26 (not 28) on Dad's side, and my 1st cousin x25 on Mom's side. (Macbeth was Crínán's uncle.)

Crínán of Dunkeld is your 27th great grandfather.
You → Eleanor Kathryn Chain (your mother) → Etta Ruth Guillory (her mother) → Charles Sherman Thomas (her father) → Leroy Thomas (his father) → Hester Ann Thomas (his mother) → Elizabeth Ellis (her mother) → Phineas Judd (her father) → Ruth Judd (his mother) → Sgt. Samuel Seymour (her father) → Hannah Seymour (his mother) → Matthew Woodruff, I (her father) → Sir David Woodroffe of Poyle (his father) → Dionyse Brouysia Calthorpe (his mother) → Edmund Calthorpe (her father) → Richard Calthorpe (his father) → Sir John Calthorpe, Kt. (his father) → Lady Elizabeth Lucy (his mother) → Sir Reynold II de Grey, 3rd Baron Grey de Ruthyn (her father) → Reginald de Grey, 2nd Baron Grey de Ruthyn (his father) → Elizabeth Hastings, Baroness Grey of Ruthin (his mother) → John Hastings, 1st Baron Hastings (her father) → Sir Henry ll de Hastings, of Ashill (his father) → Ada of Huntingdon, Heiress of Yardley (his mother) → David, 8th Earl of Huntingdon (her father) → Henry, 3rd Earl of Huntingdon (his father) → David I, King of Scots (his father) → Malcolm III, 'Canmore', King of Scots (his father) → Duncan I, King of Scots (his father) → Crínán of Dunkeld (his father)

I have several direct paths, but it's hard to get others to come up.
I wish Geni had a way to get more than one direct line of ancestry to come up at once, but sometimes you get one, and sometimes another.
I am directly descended through both my mother and father.

Judith.. I think I may have a clue. Looking below, Elizabeth Leeke is out common ancestor, so if you research her, you may be able to find the jump from her to Crinan.

Judith Arnett is your 16th cousin once removed.

You → Floyd Lee Washington, Jr (your father) → Floyd Lee Washington, Sr. (his father) → Prince Edward Washington, Sr. (his father) → Pvt. Prince William Washington (his father) → Francis Augustine Washington, Sr. (his father) → Capt. Samuel T. Washington (his father) → Mildred Washington (his mother) → Col. Francis Thornton, of Fall Hill (her father) → Col. Francis Thornton, Jr. (his father) → Alice Thornton (his mother) → Capt. Anthony Savage (her father) → Ralph Savage (his father) → Walter Savage, Esq., of Elmley (his father) → Francis Savage, Esq., of Elmley (his father) → Christopher Savage, Esq. (his father) → Sir Christopher Savage, of Chipping Campden (his father) → Elisabeth Leeke (his sister) → Sir John Leake of Sutton (her son) → Marjorie Peck (his daughter) → Robert Peck, the elder, of Beccles (her son) → Margaret Blott (his daughter) → Robert Thomas Blott (her son) → Mary Woodford (his daughter) → Joseph Woodford, I (her son) → Susanna Judd (his daughter) → Captain Phineas Judd (her son) → Phineas Judd (his son) → Elizabeth Ellis (his daughter) → Hester Ann Thomas (her daughter) → Leroy Thomas (her son) → Charles Sherman Thomas (his son) → Etta Ruth Guillory (his daughter) → Eleanor Kathryn Chain (her daughter) → Judith Arnett (her daughter)