The Lost Tribe of Joseph is 2 modern nations...
Joseph's son Ephriam is the United Kingdom.
Joseph's son Manasseh is the United States.
Joseph is an interesting tribal name because alone Joseph was not a landed tribe of ancient Israel. This is because he was written out of the will by Jacob, and his 2 sons, Ephriam and Manasseh replaced him.
The name Joseph shows up in the seal date system, though, and it identifies the March 1941 signing of the Lend Lease Treaty that established the basis for the United States to fund the United Kingdom in World War II.
Manasseh already has a seal date, in 1776, and it identifies the tribe of Manasseh as the modern United States.
By process of elimination, this leaves the tribe of Ephriam as the modern United Kingdom.
There are several interesting components to this structure that are important to note. Manasseh is the son who inherits the double portion birthright promise all the way from Abraham. This double portion aspect of Manasseh is being used on this date too, since Manasseh is in effect party to 2 of the seal dates.
Most of the rest of the tribes also carry their own native tongues. In this case Joseph, the English speaking world, breaks into 2 tribes with the same language, which is another interesting feature.
Note also that both tribes have essentially 50 base component "states."
In the case of the United States those 50 are not international sovereign governments, while in the case of Ephraim the are.
Jacob's prophecy about Ephriam:
1 Genesis 48:15-20 15וַיְבָ֥רֶךְ אֶת־ יוֹסֵ֖ף וַיֹּאמַ֑ר הָֽאֱלֹהִ֡ים אֲשֶׁר֩ הִתְהַלְּכ֨וּ אֲבֹתַ֤י לְפָנָיו֙ אַבְרָהָ֣ם וְיִצְחָ֔ק הָֽאֱלֹהִים֙ הָרֹעֶ֣ה אֹתִ֔י מֵעוֹדִ֖י עַד־ הַיּ֥וֹם הַזֶּֽה׃ 16הַמַּלְאָךְ֩ הַגֹּאֵ֨ל אֹתִ֜י מִכָּל־ רָ֗ע יְבָרֵךְ֮ אֶת־ הַנְּעָרִים֒ וְיִקָּרֵ֤א בָהֶם֙ שְׁמִ֔י וְשֵׁ֥ם אֲבֹתַ֖י אַבְרָהָ֣ם וְיִצְחָ֑ק וְיִדְגּ֥וּ לָרֹ֖ב בְּקֶ֥רֶב הָאָֽרֶץ׃ 17וַיַּ֣רְא יוֹסֵ֗ף כִּי־ יָשִׁ֨ית אָבִ֧יו יַד־ יְמִינ֛וֹ עַל־ רֹ֥אשׁ אֶפְרַ֖יִם וַיֵּ֣רַע בְּעֵינָ֑יו וַיִּתְמֹ֣ךְ יַד־ אָבִ֗יו לְהָסִ֥יר אֹתָ֛הּ מֵעַ֥ל רֹאשׁ־ אֶפְרַ֖יִם עַל־ רֹ֥אשׁ מְנַשֶּֽׁה׃ 18וַיֹּ֧אמֶר יוֹסֵ֛ף אֶל־ אָבִ֖יו לֹא־ כֵ֣ן אָבִ֑י כִּי־ זֶ֣ה הַבְּכֹ֔ר שִׂ֥ים יְמִינְךָ֖ עַל־ רֹאשֽׁוֹ׃ 19וַיְמָאֵ֣ן אָבִ֗יו וַיֹּ֙אמֶר֙ יָדַ֤עְתִּֽי בְנִי֙ יָדַ֔עְתִּי גַּם־ ה֥וּא יִהְיֶה־ לְּעָ֖ם וְגַם־ ה֣וּא יִגְדָּ֑ל וְאוּלָ֗ם אָחִ֤יו הַקָּטֹן֙ יִגְדַּ֣ל מִמֶּ֔נּוּ וְזַרְע֖וֹ יִהְיֶ֥ה מְלֹֽא־ הַגּוֹיִֽם׃ 20וַיְבָ֨רֲכֵ֜ם בַּיּ֣וֹם הַהוּא֮ לֵאמוֹר֒ בְּךָ֗ יְבָרֵ֤ךְ יִשְׂרָאֵל֙ לֵאמֹ֔ר יְשִֽׂמְךָ֣ אֱלֹהִ֔ים כְּאֶפְרַ֖יִם וְכִמְנַשֶּׁ֑ה וַיָּ֥שֶׂם אֶת־ אֶפְרַ֖יִם לִפְנֵ֥י מְנַשֶּֽׁה׃ (WLC)
1 Genesis 48:15
1 Genesis 48:15-20 15And he blessed Joseph, and said, God, before whom my fathers Abraham and Isaac did walk, the God which fed me all my life long unto this day, 16The Angel which redeemed me from all evil, bless the lads; and let my name be named on them, and the name of my fathers Abraham and Isaac; and let them grow into a multitude in the midst of the earth. 17And when Joseph saw that his father laid his right hand upon the head of Ephraim, it displeased him: and he held up his fathers hand, to remove it from Ephraims head unto Manassehs head. 18And Joseph said unto his father, Not so, my father: for this is the firstborn; put thy right hand upon his head. 19And his father refused, and said, I know it, my son, I know it: he also shall become a people, and he also shall be great: but truly his younger brother shall be greater than he, and his seed shall become a multitude of nations. 20And he blessed them that day, saying, In thee shall Israel bless, saying, God make thee as Ephraim and as Manasseh: and he set Ephraim before Manasseh. (KJV)
1 Genesis 48:15-20 15And he blessed Joseph, and said, God, before whom my fathers Abraham and Isaac did walk, the God which fed me all my life long unto this day, 16The Angel which redeemed me from all evil, bless the lads; and let my name be named on them, and the name of my fathers Abraham and Isaac; and let them grow into a multitude in the midst of the earth. 17And when Joseph saw that his father laid his right hand upon the head of Ephraim, it displeased him: and he held up his father's hand, to remove it from Ephraim's head unto Manasseh's head. 18And Joseph said unto his father, Not so, my father: for this is the firstborn; put thy right hand upon his head. 19And his father refused, and said, I know it, my son, I know it: he also shall become a people, and he also shall be great: but truly his younger brother shall be greater than he, and his seed shall become a multitude of nations. 20And he blessed them that day, saying, In thee shall Israel bless, saying, God make thee as Ephraim and as Manasseh: and he set Ephraim before Manasseh. (KJV/NC)
1 Genesis 48:15-20 15And he blessed Joseph, and said, The God before whom my fathers Abraham and Isaac did walk, the God who hath fed me all my life long unto this day, 16the angel who hath redeemed me from all evil, bless the lads; and let my name be named on them, and the name of my fathers Abraham and Isaac; and let them grow into a multitude in the midst of the earth. 17And when Joseph saw that his father laid his right hand upon the head of Ephraim, it displeased him: and he held up his father's hand, to remove it from Ephraim's head unto Manasseh's head. 18And Joseph said unto his father, Not so, my father; for this is the first-born; put thy right hand upon his head. 19And his father refused, and said, I know it, my son, I know it. He also shall become a people, and he also shall be great: howbeit his younger brother shall be greater than he, and his seed shall become a multitude of nations. 20And he blessed them that day, saying, In thee will Israel bless, saying, God make thee as Ephraim and as Manasseh: and he set Ephraim before Manasseh. (ASV)
1 Genesis 48:15-20 15And Jacob blessed Joseph his son, saying, The God before whom my fathers Abraham and Isaac walked righteously, the God who has supplied my needs from my youth to this day, 16The angel who has delivered me from all evil, bless the lads; and let them bear my name and the names of my fathers, Abraham and Isaac; and let them grow and multiply in the midst of the earth. 17And when Joseph saw that his father laid his right hand upon the head of Ephraim, it displeased him; and he held up his father's hand, to remove it from Ephraim's head to Manasseh's head. 18And Joseph said to his father, Not so, my father; for this is the first-born; put your right hand upon his head. 19But his father refused, and said, I know it, my son, I know it; he also shall become a people, and he also shall be great: but his younger brother shall be greater than he, and his descendants shall become a multitude of peoples. 20And he blessed them that day, saying, By you shall Israel bless, and they shall say, May God make you as Ephraim and as Manasseh; and thus he set Ephraim before Manasseh. (LAM)
1 Genesis 48:15-20 15And he blessed Joseph, and said, "The God before whom my fathers Abraham and Isaac walked, the God who has led me all my life long to this day, 16the angel who has redeemed me from all evil, bless the lads; and in them let my name be perpetuated, and the name of my fathers Abraham and Isaac; and let them grow into a multitude in the midst of the earth."
17When Joseph saw that his father laid his right hand upon the head of E'phraim, it displeased him; and he took his father's hand, to remove it from E'phraim's head to Manas'seh's head. 18And Joseph said to his father, "Not so, my father; for this one is the first-born; put your right hand upon his head." 19But his father refused, and said, "I know, my son, I know; he also shall become a people, and he also shall be great; nevertheless his younger brother shall be greater than he, and his descendants shall become a multitude of nations." 20So he blessed them that day, saying, "By you Israel will pronounce blessings, saying, `God make you as E'phraim and as Manas'seh'"; and thus he put E'phraim before Manas'seh. (RSV)
1 Genesis 48:15-20 15Then he blessed Joseph and said, "May the God before whom my fathers Abraham and Isaac walked, the God who has been my shepherd all my life to this day, 16the Angel who has delivered me from all harm -- may he bless these boys. May they be called by my name and the names of my fathers Abraham and Isaac, and may they increase greatly upon the earth."
17When Joseph saw his father placing his right hand on Ephraim's head he was displeased; so he took hold of his father's hand to move it from Ephraim's head to Manasseh's head. 18Joseph said to him, "No, my father, this one is the firstborn; put your right hand on his head."
19But his father refused and said, "I know, my son, I know. He too will become a people, and he too will become great. Nevertheless, his younger brother will be greater than he, and his descendants will become a group of nations." 20He blessed them that day and said, "In your name will Israel pronounce this blessing: `May God make you like Ephraim and Manasseh.'" So he put Ephraim ahead of Manasseh.(NIV)
1 Genesis 48:15-20 15He blessed Joseph, and said, 'The God before whom my fathers Abraham and Isaac did walk, the God who has fed me all my life long to this day, 16the angel who has redeemed me from all evil, bless the lads, and let my name be named on them, and the name of my fathers Abraham and Isaac. Let them grow into a multitude in the midst of the earth.'
17When Joseph saw that his father laid his right hand on the head of Ephraim, it displeased him. He held up his father's hand, to remove it from Ephraim's head to Manasseh's head. 18Joseph said to his father, 'Not so, my father; for this is the firstborn; put your right hand on his head.'
19His father refused, and said, 'I know, my son, I know. He also will become a people, and he also will be great. However, his younger brother will be greater than he, and his seed will become a multitude of nations.' 20He blessed them that day, saying, 'In you will Israel bless, saying, 'God make you as Ephraim and as Manasseh'' He set Ephraim before Manasseh. (WEB)
1 Genesis 48:15-20 15He blessed Joseph, and said, 'The God before whom my fathers Abraham and Isaac did walk, the God who has fed me all my life long to this day, 16the angel who has redeemed me from all evil, bless the lads, and let my name be named on them, and the name of my fathers Abraham and Isaac. Let them grow into a multitude in the midst of the earth.'
17When Joseph saw that his father laid his right hand on the head of Ephraim, it displeased him. He held up his father's hand, to remove it from Ephraim's head to Manasseh's head. 18Joseph said to his father, 'Not so, my father; for this is the firstborn; put your right hand on his head.'
19His father refused, and said, 'I know, my son, I know. He also will become a people, and he also will be great. However, his younger brother will be greater than he, and his seed will become a multitude of nations.' 20He blessed them that day, saying, 'In you will Israel bless, saying, 'God make you as Ephraim and as Manasseh'' He set Ephraim before Manasseh. (WEB/HNV)
1 Genesis 48:15-20 15And Jacob blessed Joseph his son, saying, The God before whom my fathers Abraham and Isaac walked righteously, the God who has supplied my needs from my youth to this day, 16The angel who has delivered me from all evil, bless the lads; and let them bear my name and the names of my fathers, Abraham and Isaac; and let them grow and multiply in the middle of the earth. 17And when Joseph saw that his father laid his right hand on the head of Ephraim, it displeased him; and he held up his father's hand, to remove it from Ephraim's head to Manasseh's head. 18And Joseph said to his father, Not so, my father; for this is the firstborn; put your right hand on his head. 19But his father refused, and said, I know it, my son, I know it; he also will become a people, and he also will be great: but his younger brother will be greater than he, and his descendants will become a multitude of peoples. 20And he blessed them that day, saying, By you will Israel bless, and they will say, May God make you as Ephraim and as Manasseh; and thus he set Ephraim before Manasseh. (BRB)
The blessing given to Ephriam and Manasseh upset their father Joseph because Jacob apeared to be changing the natural birthright promises.
The passage suggests that Manasseh would inherit Abraham's Great Nation promise while Ephraim would become a community of nations.
Of course this is how it worked out, the United Kingdom is a nation, but also a network of related nations including Canada, Australia, New Zealand and many others.